Allow devices to specify certain ro. props via TARGET_UNIFIED_DEVICE

This modifies buildinfo.sh to not set model, name, description, and
fingerprint in build.prop. These can then be set via custom init
lib.
This also fixes ota_from_target_files to function without these
props being preset.

Change-Id: Ia7dfcdea5aab7ebf51d3ab29a0d9e5751fc96663

Conflicts:
	core/Makefile
	tools/buildinfo.sh
	tools/releasetools/ota_from_target_files

PS2: fix whitespaces

Change-Id: I300171045dff9e601b66854649eeb3a8cfa9cb5f
Revert "Allow devices to specify certain ro. props via TARGET_UNIFIED_DEVICE"

This reverts commit 47c17b144f6a36d80210207288e677a1205a913c.

Until I understand all of this :)

Change-Id: I6f72913b6d9b1624c29658707b8d2657536244a5
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
Merge pull request #2 from omnirom/android-5.0

merge into lp5.0