Our webdav server has a root which is davs://mynextcloud/remote.php/webdav
When once creates a GFile out of or out of a subdirectory, and one call
g_file_get_parent(), it recurses too far up and try to query
davs://mynextcloud/remote.php which fails, resulting in a broken pathbar.
To fix that, before querying the metadata of each element of the path,
I query the "enclosing mount", then use it's root to compare the GFile
against.
This is a backport of !5830 to 3.24
d5bace3779