Add ext2, ext3, and vfat to releasetools

Support some non-standard partition that may be found in recovery.fstab

Conflicts:
	tools/releasetools/common.py

Change-Id: I0026a1d3ae5d432db10150d1a15f7bc8e7a6054b
Merge remote-tracking branch 'cm/cm-12.0' into cm-12.0