rebuild.sh: added some debug.

rebuild.sh

 #!/bin/sh
 
+/usr/bin/env
+
 BASE=""
 LATE=""
 
@@ -18,6 +20,9 @@ for dir in $CHANGED; do
     esac
 done
 
+echo "Changed base images: $BASE"
+echo "Changed late images: $LATE"
+
 for b in $BASE; do
     make -C $b push
 done