Revert change for local builds as it is breaking autopkgtests

debian/changelog

@@ -1,3 +1,10 @@
+livecd-rootfs (2.751) jammy; urgency=medium
+
+  * Revert patch for unmounting in local builds as it is causing autopkgtest
+    regressions
+
+ -- William 'jawn-smith' Wilson <jawn-smith@ubuntu.com>  Wed, 12 Jan 2022 13:43:24 -0600
+
 livecd-rootfs (2.750) jammy; urgency=medium
 
   * Do not look for a base snap on snaps of type base, because recursive

live-build/functions

@@ -158,17 +158,10 @@ teardown_mountpoint() {
 
     # ensure we have exactly one trailing slash, and escape all slashes for awk
     mountpoint_match=$(echo "$mountpoint" | sed -e's,/$,,; s,/,\\/,g;')'\/'
-
-    # Make all submounts private
-    for submount in $(awk </proc/self/mounts "\$2 ~ /$mountpoint_match/ \
-                      { print \$2 }" | LC_ALL=C sort -r); do
-        mount --make-private $submount
-    done
-
-    # Now we can unmount them
     # sort -r ensures that deeper mountpoints are unmounted first
     for submount in $(awk </proc/self/mounts "\$2 ~ /$mountpoint_match/ \
                       { print \$2 }" | LC_ALL=C sort -r); do
+        mount --make-private $submount
         umount $submount
     done
     recover_sourceslist "${mountpoint}"