prompt git needed even if installed

[LiMin]

[root@m python-jenkins-master]# python setup.py install
ERROR:root:Error parsing
Traceback (most recent call last):
  File "/root/python-jenkins-master/pbr-1.8.1-py2.7.egg/pbr/core.py", line 109, in pbr
    attrs = util.cfg_to_args(path)
  File "/root/python-jenkins-master/pbr-1.8.1-py2.7.egg/pbr/util.py", line 243, in cfg_to_args
    pbr.hooks.setup_hook(config)
  File "/root/python-jenkins-master/pbr-1.8.1-py2.7.egg/pbr/hooks/__init__.py", line 25, in setup_hook
    metadata_config.run()
  File "/root/python-jenkins-master/pbr-1.8.1-py2.7.egg/pbr/hooks/base.py", line 27, in run
    self.hook()
  File "/root/python-jenkins-master/pbr-1.8.1-py2.7.egg/pbr/hooks/metadata.py", line 26, in hook
    self.config['name'], self.config.get('version', None))
  File "/root/python-jenkins-master/pbr-1.8.1-py2.7.egg/pbr/packaging.py", line 668, in get_version
    raise Exception("Versioning for this project requires either an sdist"
Exception: Versioning for this project requires either an sdist tarball, or access to an upstream git repository. Are you sure that git is installed?
error in setup command: Error parsing /root/python-jenkins-master/setup.cfg: Exception: Versioning for this project requires either an sdist tarball, or access to an upstream git repository. Are you sure that git is installed?
[root@m python-jenkins-master]# git
usage: git [--version] [--exec-path[=GIT_EXEC_PATH]] [--html-path]
           [-p|--paginate|--no-pager] [--no-replace-objects]
           [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE]
           [--help] COMMAND [ARGS]