CA-58805: when deregistering the last VIF on an internal network, attempt to clean it up.
CA-58805: when deregistering the last VIF on an internal network, attempt to clean it up.

If someone has come along and placed other interfaces on the bridge then we log the error and abort, rather than inflict some damage on this other bridge user.

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@eu.citrix.com>

johnelse/xcp-rrdd,koushikcgit/xcp-rrdd,sharady/xcp-networkd,koushikcgit/xcp-networkd,simonjbeaumont/xcp-rrdd,johnelse/xcp-rrdd,djs55/xcp-rrdd,djs55/xcp-rrdd,djs55/squeezed,djs55/xcp-networkd,sharady/xcp-networkd,simonjbeaumont/xcp-rrdd,koushikcgit/xcp-rrdd,djs55/xcp-networkd,koushikcgit/xcp-networkd,robhoes/squeezed,koushikcgit/xcp-rrdd