Fix for missing multipath device name

Due to formatting changes in the multipath -l output
we were sometimes missing the device name for each of the
multipath devices which gave us a device of '/dev/'.  This
causes problems on detach.

Fixes Bug: #1180497

Change-Id: I6017dda149776624fac452140d3d0f5df3f5fd5a
(cherry picked from commit 565dfc65fbab1df4ec5e83be627805c313aab04b)
Merge "Fix for missing multipath device name" into stable/grizzly