Mock broke 2.6 compatibility, so pin it for now.
Mock broke 2.6 compatibility, so pin it for now.

larsbutler/coveragepy,larsbutler/coveragepy,hugovk/coveragepy,jayhetee/coveragepy,larsbutler/coveragepy,hugovk/coveragepy,blueyed/coveragepy,larsbutler/coveragepy,jayhetee/coveragepy,7WebPages/coveragepy,blueyed/coveragepy,nedbat/coveragepy,hugovk/coveragepy,7WebPages/coveragepy,7WebPages/coveragepy,blueyed/coveragepy,nedbat/coveragepy,hugovk/coveragepy,jayhetee/coveragepy,nedbat/coveragepy,larsbutler/coveragepy,nedbat/coveragepy,jayhetee/coveragepy,hugovk/coveragepy,blueyed/coveragepy,7WebPages/coveragepy,blueyed/coveragepy,nedbat/coveragepy,jayhetee/coveragepy