LU-7576 llapi: use dirname() in opendir_parent()

LU-7576 llapi: use dirname() in opendir_parent()

In opendir_parent() pass the path through dirname() so that the
resulting directory may be used with basename().

Add test_230i() to sanity.sh to ensure that lfs migrate -m tolerates
trailing slashes.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I330717da540618052bc5efbb5df9cbe6c4194050
Reviewed-on: http://review.whamcloud.com/17796
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>