build: Ensure /system unmounted at install start

Account for the possibility that a user has mounted system manually
before installing the FullOTA package.

Change-Id: I97d0540676a7ce98762545e76ecb1a7f6335d204
Remove nulls from the edify generator.

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

Change-Id: I0c52335a27f7ae974279fde1c2461b2dba24d263
Add graphite flags

Change-Id: I482279c0b9448cb05d56ce183affa30a4ac7bd4f
Signed-off-by: Paul Beeler <pbeeler80@gmail.com>
Merge tag 'android-5.0.1_r1' of https://android.googlesource.com/platform/build into L

Android 5.0.1 release 1