fab install_contrail fail on centos with yaml import error

[Harish Kumar]

sshpass -p c0ntrail123 ssh -t -t -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null root@10.204.216.201 '(

                export HA_TEST=;
                cd fabric-utils;
                fab install_contrail:reboot=False
    )'
Warning: Permanently added '10.204.216.201' (RSA) to the list of known hosts.
Traceback (most recent call last):
2016-01-11 18:15:08:828538: File "/usr/lib/python2.7/site-packages/fabric/main.py", line 658, in main
2016-01-11 18:15:08:828631: docstring, callables, default = load_fabfile(fabfile)
2016-01-11 18:15:08:828864: File "/usr/lib/python2.7/site-packages/fabric/main.py", line 165, in load_fabfile
2016-01-11 18:15:08:828932: imported = importer(os.path.splitext(fabfile)[0])
2016-01-11 18:15:08:829073: File "/root/fabric-utils/fabfile/__init__.py", line 19, in <module>
2016-01-11 18:15:08:829125: from tasks.tester import *
2016-01-11 18:15:08:829235: File "/root/fabric-utils/fabfile/tasks/tester.py", line 7, in <module>
2016-01-11 18:15:08:829285: import yaml
2016-01-11 18:15:08:829396: ImportError: No module named yaml
2016-01-11 18:15:08:829565: Connection to 10.204.216.201 closed.
+ debug_and_die 'fab install_contrail failed'
+ local 'message=fab install_contrail failed'
+ '[' 1 = 1 ']'
+ echo 'Testbed is set to be locked on failure'
Testbed is set to be locked on failure
+ [[ fab install_contrail failed =~ Test failures exceed ]]

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/16229
Submitter: Harish Kumar (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/16229
Committed: http://github.org/Juniper/contrail-fabric-utils/commit/5bc62ff3c9fb1d4c052b342a3abd216c14244395
Submitter: Zuul
Branch: master

commit 5bc62ff3c9fb1d4c052b342a3abd216c14244395
Author: hkumarmk <email address hidden>
Date: Tue Jan 12 10:32:28 2016 +0530

Moved yaml import to run_rally method to avoid fab run failures

Centos doesnt have PyYAML installed by default, and thus fab
tasks fail with import error as tester.py is importing yaml. Fix is to
move the import to the method run_rally.

Change-Id: I2744ae86f75a366d616498b3b5558ec5d5f755df
Closes-Bug: #1533053