CLEANUP: mworker: rename mworker_pipe to mworker_sockpair

The function mworker_pipe_register_per_thread() is called this way
because the master first used pipes instead of socketpairs.

Rename mworker_pipe_register_per_thread() to
mworker_sockpair_register_per_thread() in order to be more consistent.

Also update a comment inside the function.
1 file changed