Improved git cl patch generated commit message to include patchset information and a link to it.
Improved git cl patch generated commit message to include patchset information
and a link to it.

BUG=

Review URL: https://codereview.chromium.org/731473002

git-svn-id: bd64dd6fa6f3f0ed0c0666d1018379882b742947@292940 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

svn2github/chromium-depot-tools,svn2github/chromium-depot-tools,svn2github/chromium-depot-tools