fs: make sure VDI.deactivate, VDI.activate works
fs: make sure VDI.deactivate, VDI.activate works

VDI.activate expects tapdisk to be in a 'paused' state, not a 'closed' one.

xapi-project/message-switch,xapi-project/message-switch,djs55/message-switch,djs55/message-switch-1,djs55/message-switch,djs55/message-switch-1,xapi-project/message-switch,djs55/message-switch,djs55/message-switch-1