70-update_background_image: Just print a warning msg for unrecognized mirror

Signed-off-by: Diego Giovane Pasqualin <dpasqualin@c3sl.ufpr.br>

scripts/70-update_background_image

@@ -44,6 +44,7 @@ DISTNAME=$(echo $LEMIRROR | cut -d- -f1 | tr '[:lower:]' '[:upper:]')
 MIRROR=$(echo $LEMIRROR | cut -d- -f2)
 HOST=$(echo $LEHOST | cut -d. -f1)
 
+RELEASE=""
 case "$MIRROR" in
     "stable")
         echo "Generating stable version, keeping background untouched."
@@ -58,12 +59,13 @@ case "$MIRROR" in
     "unstable")
         RELEASE="Alpha"
         ;;
-    *)
-        echo "ERROR: Unrecognized mirror $MIRROR"
-        exit 1
-        ;;
 esac
 
+if [ -z "$RELEASE" ]; then
+    echo "WARNING: Unrecognized mirror $MIRROR"
+    exit 0
+fi
+
 for IMAGE in $IMAGES; do
     if [ -f $IMAGE ]; then
         convert -font helvetica -fill "#f3f2ed" -pointsize 200 -gravity center \