docker_mount: Fix threading issue
docker_mount: Fix threading issue

There was an issue that when image-scanner ran threaded, the
XFS conditional was not being detected properly like caused
by a lack of parans on a rstrip call.

simon3z/image-scanner,maxamillion/image-scanner,simon3z/image-scanner,maxamillion/image-scanner,baude/image-scanner,simon3z/image-scanner,baude/image-scanner,baude/image-scanner,maxamillion/image-scanner