Update API usage for source

replacing any instance of op->source_info with GetCowSourceinfoData as
that's what we're really looking for. This function will return the 48
bits associated with the source and not the extra bits that will store
type + other information. We should never be making a reference to
op->source_info directly as that has no real meaning, we should be
masking for the data that we really need

Test: cow_api_test
Change-Id: I259c790efdd13c61a4599e9edfc75cf0ba000c61