Currently a process was being forked off for each individual file
this class wanted to inspect with rpmdeps. This converts it to use
rpmdeps-oecore which allows batch processing of these dependencies.
For do_package for perl, this reduced the time by about 1 minute (33%).
(From OE-Core rev: 548037acd63bd4859f8de8d23a3d12f36ce9f97f)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>