CA-110585: Setting snapshot_time for VDI before passing it to SM during
VDI.snapshot

Issue:The vdi snapshot time was being set after SM returned from
creating vdi.

Fix: The snapshot_time is now set before it being passed to SM.

Signed-off-by: Ravi Pandey <ravi.pandey@citrix.com>
Merge pull request #1886 from ravippandey/CA-110585

CA-110585: Passing correct snapshot_time during VDI.snapshot