add git.mozilla.org to VCS_MAPPINGS

B2G builds are now using git.mozilla.org as the repository of record.
bug 866874 - redirect bp- prefix on crash_id
Merge pull request #332 from peterbe/bug866874-redirect-bp--prefix-on-crash_id

bug 866874 - redirect bp- prefix on crash_id
Merge pull request #330 from luser/master

Add git.mozilla.org to VCS_MAPPINGS
bug 866873 - robots.txt accordingly
Merge pull request #333 from peterbe/bug866873-robotstxt-accordingly

bug 866873 - robots.txt accordingly