Register provider succeeds when failures occur

The provider actions where capturing the keystone cmd error and just
logging them as errors to the log, resulting in a converged node that
is unusable.  These errors should be raised as exceptions to allow
for these configuration errors to be debugged earlier.

Change-Id: I0990dc8386f5999dc96b6cedfca86a762f031953
Closes-Bug: #1370678
Merge "Register provider succeeds when failures occur"