Check the flashcopy mapping relationship before deleting volume.
Currently the volume stays in 'deleting' if there is fcmapping
for IBM storwize/SVC driver. Change it to stop the fcmapping
first if the volume is the target volume of the fcmapping.
DocImpact
Change-Id: I99fdbbeda4151d4e02ebd6a0ede9a49eb2abc618
Closes-Bug: 1534118
