[bootstrap/_deb_common] Re-fix the always-install-backports

* This bug seems to come back every time it's fixed :(

bootstrap/_deb_common.sh

@@ -54,10 +54,10 @@ AddBackportRepo() {
 
             echo $BACKPORT_SOURCELINE >> /etc/apt/sources.list.d/"$BACKPORT_NAME".list
             apt-get update
-            apt-get install -y --no-install-recommends -t "$BACKPORT_NAME" $augeas_pkg
-            augeas_pkg=
         fi
     fi
+    apt-get install -y --no-install-recommends -t "$BACKPORT_NAME" $augeas_pkg
+    augeas_pkg=
 
 }