[ACS41][Patch Request] CLOUDSTACK-1315: Fix NPE when try to upgrade network from VR to SRX-F5

[Sheng Yang]

commit 27ba0208f068e60f588d25a5d0ad9c4d6503ad14
Author: Sheng Yang <sheng.y...@citrix.com>
Date:   Wed Mar 6 16:49:44 2013 -0800

    CLOUDSTACK-1315: Fix NPE when try to upgrade network from VR to SRX-F5

    Still return a valid object when reverting non-existed rules.

Thanks.

--Sheng