Base python 2.7 skip list on parsed names

We keep a list of libraries that should only be installed on python 2.6,
but the check to see if a requirement matches that list was only doing
a simple string equality, which would miss attempts to install version
specified instances of one of them.

Instead, use pkg_resources to parse the potential requirements line and
operate on the parsed project name.

Change-Id: If64e4b2ee6696a0531e3ed6099e63372d47bc851
Merge "Base python 2.7 skip list on parsed names"