Add BOARD_DONT_BUILD_USERDATA_IMG
Add BOARD_DONT_BUILD_USERDATA_IMG

So board config can choose to not build userdata.img.

Change-Id: I1e6024abb7806492468801e49075fa24c05d2dd1

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