New testsuite fail01 to test failed deployments because of lack of resources

Updated openstack_lib.robot for adding new keyword 'Check NS Servers In VIM'
needed by fail01 test.

Change-Id: Ib602d27d8643e9c4b7c1029533258b79df5e86a8
Signed-off-by: aguilard <e.dah.tid@telefonica.com>
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>