hooks: Remove /etc/.pwd.lock and /run/mount/utab

When the zero-byte file /etc/.pwd.lock is present in the ISO image,
diffoscope will abort
(https://salsa.debian.org/reproducible-builds/diffoscope/-/issues/367)

This file will be generated when needed, so it can be removed from the
image.

Cleanup /run/mount/utab (and its directory)

share/hooks/normal/8070-remove-temporary-files.hook.chroot

@@ -10,3 +10,13 @@ do
 	mkdir -p ${_DIRECTORY}
 	chmod 1777 ${_DIRECTORY}
 done
+
+# Remove the old lock file which will be generated when needed
+rm -f /etc/.pwd.lock
+
+# Remove /run/mount/utab of util-linux libmount (and its directory)
+# The file and directory will be generated when needed
+if [ -d /run/mount ]; then
+	rm -f /run/mount/utab
+	rmdir --ignore-fail-on-non-empty /run/mount
+fi