Update the requirements-py2.txt file

It appears the openstack requirements proposal bot
does not currently update all the right files, this
bug is filed @ bug 1371936 so until that is fixed
this proposes the same change to the py2 requirements
file that just got merged into the py3 file.

Change-Id: I03dfc1579f44f930acaf92ef47c13829ffcbf35b
Merge "Update the requirements-py2.txt file"