guard against two level subdir moves

this has never worked since the -wholename check only works for
one level deep

src/scripts/mvvolume.sh

@@ -27,7 +27,7 @@ if [[ "${BOX_ENV}" == "test" ]]; then
 fi
 
 # copy and remove - this way if the copy fails, the original is intact
-# the find logic is so that move to a subdir works (and we also move hidden files)
+# the find logic is so that move to a one level subdir works (and we also move hidden files)
 find "${source_dir}" -maxdepth 1 -mindepth 1 -not -wholename "${target_dir}" -exec cp -ar '{}' "${target_dir}" \;
 find "${source_dir}" -maxdepth 1 -mindepth 1 -not -wholename "${target_dir}" -exec rm -rf '{}' \;
 # this will fail if target is a subdir or if source is a mountpoint