property_service: Added vendor build properties to load_all_props

Signed-off-by: Daniel Rosenberg <drosen@google.com>

(cherry picked from commit b95122205dba535215ff6b011ef8009933c55d3b)

Bug: 18281574
Change-Id: Id1f1c4e9e0d1bfbcae3995fb7966d18bf7d6e06d
1 file changed