Fix failed to delete the EIP resource

When AWS::EC2::EIP is failed to associate with
the server, it can't be delete. So we attempt
to disassociate and to catch the exception, and to
check if not associate we just ignore it while deletion.

Change-Id: I6a34398f27d6b21de9209de70bf8cc3c77d27149
Closes-Bug: #1334497
Merge "Fix failed to delete the EIP resource"