XOP-311, SCTX-942, CA-88975: Modifications for VM Shutdown
	First attempt to perform a clean_shutdown
	If clean_shutdown fails, then perform a hard_shutdown

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
Adding warn level logging when unable to perform clean_shutdown

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
XOP-311: Printing exception along with warn level log.
Also set in_product_since to clearwater.

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
XOP-311: Moving up update_vbd_operations and update_vif_operations in
message_forwarding.ml
Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
Correcting merge build errors
Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
Merge pull request #1195 from zli/xenserver/clearwater-XOP-311

CLEARWATER: XOP-311: Modifications for VM Shutdown