This also refactors the lcow and windows
snapshotters to use go-winio's utility functions for checking the
filesystem type.
Signed-off-by: Eric Hotinger <ehotinger@gmail.com>
The race usually happens when `closeHandle()` and `prepareIo()` are called
concurrently; the former tries to set `closing` to `true` the latter tries
to read its value.
In order to avoid this issue, we added a lock around the variable.
Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>
