raft/membership: cleanup state dir in tests
raft/membership: cleanup state dir in tests

Signed-off-by: Alexander Morozov <2043cda4df124b840b98ee1c4307c199042efdf7@gmail.com>

dperny/swarmkit-1,allencloud/swarmkit,aaronlehmann/swarmkit,dperny/swarmkit-1,alyyousuf7/swarmkit,elifa/swarmkit,fate-grand-order/swarmkit,docker/swarmkit,elifa/swarmkit,sungwonh/swarmkit,docker/swarmkit,deljuven/swarmkit,yongtang/swarmkit,allencloud/swarmkit,jlhawn/swarmkit,yongtang/swarmkit,deljuven/swarmkit,aaronlehmann/swarmkit,cheyang/swarmkit,cezarsa/swarmkit,vasil-yordanov/swarmkit,Noyan759/swarmkit,diogomonica/swarmkit,jlhawn/swarmkit,RenaudWasTaken/swarmkit,Noyan759/swarmkit,cezarsa/swarmkit,AliyunContainerService/swarmkit,fate-grand-order/swarmkit,alyyousuf7/swarmkit,sungwonh/swarmkit,cheyang/swarmkit,AliyunContainerService/swarmkit,RenaudWasTaken/swarmkit,diogomonica/swarmkit,yp-engineering/swarmkit,yp-engineering/swarmkit,vasil-yordanov/swarmkit