Clean up no-longer-used recipes stuff

- Remove buildbot logic
- Remove non-Gerrit logic
- Remove master, slave, and build number properties

Bug: skia:6473
Change-Id: I203d523f3a0e03f933c0c48d29c7aabac503b2b9
Reviewed-on: https://skia-review.googlesource.com/12625
Reviewed-by: Ravi Mistry <rmistry@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
119 files changed