Make an explicit RC device selection override any GID hint,
matching the --rc-device contract. A stale hint should not
prevent a named HCA from starting.
Query the selected port before allocating the protection domain and fail initialization when that query fails. Continuing with a zero LID advertises an invalid endpoint on InfiniBand and turns a clear startup error into a later RDMA data-plane failure.
Ben McClelland
51c28734fb