NetApp fix eseries concurrent vol map failure

This fixes the issue while mapping volume to host
when the requests are very close in time proximity.
The map operation has been synchronized.

Change-Id: I2e120d84d3b96faa4ab8d4324e70a089bcddeaa5
Closes-bug: #1312685
(cherry picked from commit 209c09a76f5e90aaa2899804686e6a513703d887)