CA-125187: Don't automatically dismiss VDI operations during copy

We still want to allow VDI.snapshot while a VDI is being copied.

Signed-off-by: John Else <john.else@citrix.com>
CA-126097: Block clone of live VDIs

Signed-off-by: John Else <john.else@citrix.com>
Fix test case name

Signed-off-by: John Else <john.else@citrix.com>
Add a case to a unit test

Signed-off-by: John Else <john.else@citrix.com>