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.

Change-Id: I437995c0d450c01586bf66740b4dd618d6c3dc19

stackforge/group-based-policy-ui,noironetworks/group-based-policy-ui,noironetworks/group-based-policy-ui,stackforge/group-based-policy-ui,stackforge/group-based-policy-ui,noironetworks/group-based-policy-ui,noironetworks/group-based-policy-ui,stackforge/group-based-policy-ui