Fix the root folder detection for mounts points to '/'
Fix the root folder detection for mounts points to '/'

This fixes an endless recursion for the case, that an external storage is mounted to "/". Then the `isRootFolder` method never evaluated to true, because a trailing slash was the actual diff between the current path and the root folders path.

Signed-off-by: Morris Jobke <7f550a9f4c44173a37664d938f1355f0f92a47a7@morrisjobke.de>

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