package_rpm: Remove need for locking

package_rpm: Remove need for locking

Currently if multiple package tasks are running against a recipe, package_rpm
is restricted to the slowest speed of them due to the locking. This patch
explicitly ignores the opkg/debian artefacts and hence allows a speedup.

It also removes an issue were a Ctrl+C interrupting a deb.ipk packaging task
would end up with CONTROL/DEBIAN files in the spec file resulting in a build
failure.

(From OE-Core rev: 4c3b3a57aa9ced231f5c0340920195c15a26f2b1)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>