CBQE-1400 remove diag.zip files from vm.

Change-Id: I0919cc84a5d1d4e1253679dc7f230d41a43a24bd
Reviewed-on: http://review.couchbase.org/27091
Tested-by: Thuan Nguyen <soccon@gmail.com>
Reviewed-by: Ketaki Gangal <ketakigangal@gmail.com>