remove python 2.6 trove classifier
remove python 2.6 trove classifier

OpenStack projects are no longer being tested under Python 2.6, so
remove the trove classifier implying that this project supports 2.6.

Closes-Bug:#1519510
Change-Id: I4207349597abc8d3d05d6d210d35f438534a5997

openstack/congress,ramineni/my_congress,ramineni/my_congress,ramineni/my_congress,ramineni/my_congress,openstack/congress