Since , Pyroute forks the namespace creation to avoid calling
destructive routine "libc.unshare(CLONE_NEWNET)" from the main
process. This implementation uses sockets between both processes
to return any error feedback sent from the child process.
This patch implements the same fork without any communication. If
the child process raises an exception other than "OSError(EEXIST)",
the child process returns 1 that is read by the the main process,
that raises a "RuntimeError" exception.