rdma: correct some spelling mistakes

Change-Id: Ib7018aa8a79d36ab942516457a79039cb3e67355
BUG: 1088849
Reported-by: Patrick Matthäi <pmatthaei@debian.org>
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: http://review.gluster.org/7498
Reviewed-by: Vikhyat Umrao <vumrao@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>