Add default app image format property
Add default app image format property

Defaults to lz4.

Bug: 22858531
Change-Id: Iab65a650b67e7bde1fc3582f166d4f17a0367749

xorware/android_build,xorware/android_build,xorware/android_build,xorware/android_build,xorware/android_build