Description of problem:
Improve glfs_set_volfile_server();

RDMA transport was never supported for management connection before, but glfs_set_volfile_server() allowed it and the gluster code silently fall back to tcp with out a warning, this gave a chance to people assume that mgmt connection supports rdma along with tcp and unix.

We need to deprecate the rdma support by stating to splash warning at the usage.

Also add better defense code on port and transport;


Version-Release number of selected component (if applicable):
mainline