No mount cleanup after kill -9 and restart

[Juul]

After killing ouisync with kill -9 due to issue #171 and then re-starting ouisync with ouisync start the ~/ouisync directory still contains what appears to be both a normal empty directory for one repo (locally created repo) and one hung mountpoint in a weird state for a repo created by another peer and synced to this peer:

$ ls -l ~/ouisync/
ls: cannot access '/home/<user>/ouisync/eq test 1': Transport endpoint is not connected
total 0
d????????? ? ?    ?      ?            ? 'eq test 1'
dr-xr-xr-x 1 root root 193 Dec 31  1969  phone

Stopping ouisync with ctrl-c (which worked this time), then manually unmounting /home/<user>/ouisync/eq test 1 and re-starting ouisync fixed the issue.

ouisync should probably recover better from an unclean exit by e.g. detecting stale ouisync mounts and unmounting them

[Juul]

I should add that after a kill -9 I can't unmount repos at all without sudo, which is interesting since at no point did I use sudo to install or run ouisync:

$ umount ~/ouisync/phone 
umount: /home/<user>/ouisync/phone: Transport endpoint is not connected