updated:

Following latest error logs, tried to install pypy using sudo apt-get install pypy 
and reran sudo tox egenconfig command but still failed:
Collecting appdirs>=1.3.0 (from os-client-config>=1.13.1->python-openstackclient>=2.1.0->-r /home/stack/kingbird/requirements.txt (line 41))
  Downloading appdirs-1.4.0-py2.py3-none-any.whl
Collecting argparse (from unittest2>=1.0.0->testtools>=1.4.0->-r /home/stack/kingbird/test-requirements.txt (line 14))
  Downloading argparse-1.4.0-py2.py3-none-any.whl
Collecting linecache2 (from traceback2->testtools>=1.4.0->-r /home/stack/kingbird/test-requirements.txt (line 14))
  Downloading linecache2-1.0.0-py2.py3-none-any.whl
Collecting pyasn1>=0.1.7 (from paramiko>=1.16.0->tempest-lib>=0.14.0->-r /home/stack/kingbird/test-requirements.txt (line 20))
  Downloading pyasn1-0.1.9-py2.py3-none-any.whl
Collecting cryptography>=1.1 (from paramiko>=1.16.0->tempest-lib>=0.14.0->-r /home/stack/kingbird/test-requirements.txt (line 20))
  Downloading cryptography-1.4.tar.gz (399kB)
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "app_main.py", line 72, in run_toplevel
      File "app_main.py", line 578, in run_it
      File "<string>", line 1, in <module>
      File "/tmp/pip-build-pis670/cryptography/setup.py", line 53, in <module>
        "cryptography 1.0 is not compatible with PyPy < 2.6. Please "
    RuntimeError: cryptography 1.0 is not compatible with PyPy < 2.6. Please upgrade PyPy to use this library.

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-pis670/cryptography/

ERROR: could not install deps [-r/home/stack/kingbird/requirements.txt, -r/home/stack/kingbird/test-requirements.txt]; v = InvocationError('/home/stack/kingbird/.tox/pypy/bin/pip install -U -r/home/stack/kingbird/requirements.txt -r/home/stack/kingbird/test-requirements.txt (see /home/stack/kingbird/.tox/pypy/log/pypy-1.log)', 1)
pep8 develop-inst-noop: /home/stack/kingbird
pep8 installed: alembic==0.8.7,amqp==1.4.9,anyjson==0.3.3,appdirs==1.4.0,Babel==2.3.4,beautifulsoup4==4.5.0,cachetools==1.1.6,cliff==2.1.0,cmd2==0.6.8,contextlib2==0.5.4,debtcollector==1.6.0,decorator==4.0.10,enum34==1.1.6,eventlet==0.19.0,fasteners==0.14.1,flake8==2.2.4,funcsigs==1.0.2,functools32==3.2.3.post2,futures==3.0.5,futurist==0.16.0,greenlet==0.4.10,hacking==0.10.2,httplib2==0.9.2,iso8601==0.1.11,Jinja2==2.8,jsonpatch==1.14,jsonpointer==1.10,jsonschema==2.5.1,keystoneauth1==2.10.0,keystonemiddleware==4.7.0,-e git+https://github.com/openstack/kingbird.git@43f048deef164479fd6f89970c7589937b3bb33f#egg=kingbird,kombu==3.0.35,logutils==0.3.3,Mako==1.0.4,MarkupSafe==0.23,mccabe==0.2.1,monotonic==1.1,msgpack-python==0.4.8,netaddr==0.7.18,netifaces==0.10.4,openstacksdk==0.9.1,os-client-config==1.18.0,osc-lib==0.4.1,oslo.concurrency==3.12.0,oslo.config==3.13.0,oslo.context==2.7.0,oslo.db==4.8.0,oslo.i18n==3.8.0,oslo.log==3.12.0,oslo.messaging==5.5.0,oslo.middleware==3.15.0,oslo.policy==1.12.0,oslo.rootwrap==5.0.0,oslo.serialization==2.11.0,oslo.service==1.13.0,oslo.utils==3.16.0,oslo.versionedobjects==1.13.0,Paste==2.0.3,PasteDeploy==1.5.2,pbr==1.10.0,pecan==1.1.2,pep8==1.5.7,pika==0.10.0,pika-pool==0.1.3,positional==1.1.1,prettytable==0.7.2,pycadf==2.3.0,pyflakes==0.8.1,pyinotify==0.9.6,pyparsing==2.1.5,python-cinderclient==1.8.0,python-dateutil==2.5.3,python-editor==1.0.1,python-glanceclient==2.2.0,python-keystoneclient==3.3.0,python-neutronclient==5.0.0,python-novaclient==5.0.0,python-openstackclient==2.6.0,pytz==2016.6.1,PyYAML==3.11,repoze.lru==0.6,requests==2.10.0,requestsexceptions==1.1.3,retrying==1.3.3,rfc3986==0.3.1,Routes==2.3.1,simplejson==3.8.2,singledispatch==3.4.0.3,six==1.10.0,SQLAlchemy==1.0.14,sqlalchemy-migrate==0.10.0,sqlparse==0.2.0,stevedore==1.16.0,Tempita==0.5.2,unicodecsv==0.14.1,waitress==0.9.0,warlock==1.2.0,WebOb==1.6.1,WebTest==2.0.23,wrapt==1.10.8
pep8 runtests: PYTHONHASHSEED='2015100914'
pep8 runtests: commands[0] | flake8
______________________________________________________________________________________________ summary ______________________________________________________________________________________________
ERROR:   py34: could not install deps [-r/home/stack/kingbird/requirements.txt, -r/home/stack/kingbird/test-requirements.txt]; v = InvocationError('/home/stack/kingbird/.tox/py34/bin/pip install -U -r/home/stack/kingbird/requirements.txt -r/home/stack/kingbird/test-requirements.txt (see /home/stack/kingbird/.tox/py34/log/py34-1.log)', 1)
  py27: commands succeeded
ERROR:   pypy: could not install deps [-r/home/stack/kingbird/requirements.txt, -r/home/stack/kingbird/test-requirements.txt]; v = InvocationError('/home/stack/kingbird/.tox/pypy/bin/pip install -U -r/home/stack/kingbird/requirements.txt -r/home/stack/kingbird/test-requirements.txt (see /home/stack/kingbird/.tox/pypy/log/pypy-1.log)', 1)
  pep8: commands succeeded