NetApp fix attach fail for already mapped volume

This patch fixes the error raised during mapping of a volume
to the host during attach operation if the volume is already
mapped to the host.

Change-Id: I4f711e7ac18eea0dfddab65fd85a3601fe967a88
Closes-bug: #1310659
(cherry picked from commit dcec1b84f4d3462fc408f4152f4c89b8df79d629)
Merge "NetApp fix attach fail for already mapped volume" into stable/icehouse