Fix incremental build number on Darwin

Darwin does not include sha1sum, but it should have openssl.

Change-Id: If2b685c1478f9486bed21dfba0c655d9e02db72b
Merge "Fix incremental build number on Darwin" into cm-10.2
Use openssl instead of sha1sum

Change-Id: Iab8a74d4af6646104cb23312853f811a38bdec0d
build: Don't run backuptool on GMS builds

Change-Id: I5dde27f9d16b88049171db9805221d92e67f3e5d
Merge branch 'cm-10.2' of git://github.com/CyanogenMod/android_build into cm-10.2