installd: Skip dexroot-on-cache for user builds

Change-Id: Ia724cce7e904558654f5a0ed853e817c768d1383
Add support for QC's time_daemon

Enabled by BOARD_USES_QC_TIME_SERVICES=true, it requires the device
to provide its own time_daemon executable and libtime_genoff.so
proprietaries. The library should be copied by the device's setup
config to $OUT/obj/lib for linkage (and pushed to the final build,
obviously)

Change-Id: Ie6964dbe2692dc33fc04093a5b89b6922d8443c8