pgw: Wait for component to get out of SUT's Diameter SUSPECt list

Similar fix was applied to GGSN_Tests when adding Diameter support in
commit 0bcfd9de8ff359673ddb71e013dbad44bf9510cc.

Change-Id: I95ddf6c1048f0bfd6590bae574aea15c4fc2710b
1 file changed