Fixed mounting /system when 'override_prop' is enabled.

Change-Id: I59f035498c2a2d65869cb7f7e6ea9e311b9757be

Conflicts:
	tools/releasetools/ota_from_target_files
Edify: Add AssertSomeBaseband

Allow releasetools.py to assert a baseband version. Works just like
AssertSomeBootloader.

Change-Id: Ic8eb341cef1d777d983be25ba21a3bc545819c29
Remove nulls from the edify generator.

These would break the scripts. WTF are they doing here?

Change-Id: I0c52335a27f7ae974279fde1c2461b2dba24d263

Conflicts:
	tools/releasetools/edify_generator.py