CA-77519: wait for events before calling {VBD,VIF}.remove in {VBD,VIF}.unplug
CA-77519: wait for events before calling {VBD,VIF}.remove in {VBD,VIF}.unplug

If we call remove too soon then the event handler fails to set currently_attached to false.

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

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