build: update prebuilt chromium script

Prebuilt chromium: update for lollipop

Change-Id: I4e34feb26c1b4bec10fb751a10dbc52579d7cd07

Prebuilt chromium: Run a check for target device directory

this should fix the issue that arises if device fails and device is built again,
chromium will error out because it thinks the prebuilt files exist (which they are
not, directories are just created).

Signed-off-by: Ayysir <ayysir@aospal.com>
Change-Id: I595cab268e66c738ccae9900150b36d7f9626a6e
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.

Conflicts:
	core/Makefile
	tools/releasetools/ota_from_target_files

Change-Id: I36511fc3e37ddc4bbe9636c340de26c0c614d363
Signed-off-by: cj360 <ayunker551@gmail.com>
Edify: Add/Update abort messages for some asserts

* If a bootloader or baseband assert is not satisfied, print the
  versions that are supported by the package as well as the version
  on the device.

Change-Id: I958d49281c51bd4e60d596a727bb94cfc4a21909
ota: Build uboot bootable images when necessary

Conflicts:
	core/Makefile
	tools/releasetools/common.py

Change-Id: I18996bb1f5377bbf369fb41774aaa1f5821e7d1f
Enable QCOM_BSP_LEGACY flag for pre-8974 targets

Change-Id: I895f1b1cbad0d260e1bca87ccb61e6194de023fd
Allow specifying kernel toolchain and prefix

Change-Id: Ib75cfe772e073f2196455f3e3dfba247f6b3feff
build: recovery: Support adding device-specific items

(cdesai): Also add the relevant parts from koush's
commit 7fd5a89df5ec3961c9aedfd2afad50d6d2561056
"Add initial support for charge mode. also support recovery/root in the device tree to easily copy props into recovery images."

Change-Id: I25205e68282680932917016646dabd1abadbfce6
build: Only mount /system if not mounted

The commit on which this depends takes care of the mount error if /data
is already mounted during install. This commit takes care of the error
if /system is already mounted.

Change-Id: I97d0540676a7ce98762545e76ecb1a7f6335d204