Remove Python 2.6 from setup.cfg

Python 2.6 support is dropped so it should be removed from setup.cfg.

Change-Id: I28b205c8a8027de4168b65f272983b38bb09dd2d
Updated from global requirements

Change-Id: I47e73b8f59bc8afd91e9cafaa792a537dd214238
Merge "Updated from global requirements"
Merge "Remove Python 2.6 from setup.cfg"