[CRIU] Use inherit-fd from runc patches

[Adrian Reber]

So with the help of Andrei I was able to drop all the patches I had for the
RPC inherit-fd call-back. This means that 'criu service' still does not
support inherit-fd. I am sending out one cleanup patch I still have
and which could be applied (criu/action-scripts: remove duplicate code)
and a feature check patch which I am using in runc to detect if it makes
sense to run the test case for external network namespaces.