Call ucma_ib_init() during startup

ucma_ib_init() was removed from ucma_init() to avoid
recursive callback issues when using the librspreload
library over rsockets.  Although rsockets calls ucma_ib_init,
other pieces of the code do not.  The result is that
ibacm ends up being disabled unless rsockets has been
used.  Fix this by calling ucma_ib_init() where needed.

This problem was reported by Jens Domke
<domke.j.aa@m.titech.ac.jp>

Signed-off-by: Sean Hefty <sean.hefty@intel.com>