NXDRIVE-170: Fix readonly lock/unlock race condition
NXDRIVE-170: Fix readonly lock/unlock race condition

rsoumyassdi/nuxeo-drive,arameshkumar/base-nuxeo-drive,loopingz/nuxeo-drive,ssdi-drive/nuxeo-drive,ssdi-drive/nuxeo-drive,arameshkumar/nuxeo-drive,arameshkumar/nuxeo-drive,arameshkumar/nuxeo-drive,rsoumyassdi/nuxeo-drive,DirkHoffmann/nuxeo-drive,arameshkumar/base-nuxeo-drive,DirkHoffmann/nuxeo-drive,DirkHoffmann/nuxeo-drive,loopingz/nuxeo-drive,arameshkumar/nuxeo-drive,rsoumyassdi/nuxeo-drive,arameshkumar/base-nuxeo-drive,loopingz/nuxeo-drive,loopingz/nuxeo-drive,rsoumyassdi/nuxeo-drive,DirkHoffmann/nuxeo-drive,ssdi-drive/nuxeo-drive,arameshkumar/base-nuxeo-drive,DirkHoffmann/nuxeo-drive,loopingz/nuxeo-drive