Revert "svc/squashdir-mount.initd: minor prefix slash (/) fix (lets fix for good)"

This reverts commit 0706a3e60e12ba1c0b75081361d6f17de44b66ee.
Revert "svc/sdr.{ba,z}sh: (still) fix prefix slash (/)"

This reverts commit 88a4c1937b7c86a3eeeda5b93b61ecb11aed5e2d.