This reverts commit f99d599930.
Due to it break vpc function and block regression test.
Conflicts:
server/src/com/cloud/network/router/VirtualNetworkApplianceManagerImpl.java
server/src/com/cloud/network/router/VpcVirtualNetworkApplianceManagerImpl.java
server/test/com/cloud/network/router/VpcVirtualNetworkApplianceManagerImplTest.java