Tweak ordering of snapshot URLs

Put snapshot.d.o last in the list in jigdo files, to reduce load on
the service.

debian/changelog

@@ -18,6 +18,10 @@ debian-cd (3.1.24) UNRELEASED; urgency=medium
   * Switch bootloader from silo to grub-ieee1275 on sparc
   * Switch bootloader from silo to grub-ieee1275 on sparc64
 
+  [ Steve McIntyre ]
+  * Tweak ordering of snapshot URLs - put snapshot.d.o last in the list in
+    jigdo files, to reduce load on the service.
+
  -- Holger Levsen <holger@debian.org>  Wed, 20 Feb 2019 14:12:16 +0100
 
 debian-cd (3.1.23) unstable; urgency=medium

tools/jigdo_cleanup

@@ -40,22 +40,22 @@ cat $jigdo | awk -v ISO="$iso" -v TEMPLATE="$template" -v DISCINFO="$discinfo" -
 ' > $jigdo.1
 mv -f $jigdo.1 $jigdo
 
-# Snapshot URL
-if [ "$snapurl"x != ""x ] ; then
-    echo "$snapurl" >> $jigdo
-fi
-
 # If some fallbacks were specified, output a servers section with the
 # URLs. The entries of the variable are expected to be already of the
 # form "Label=http://some.url/"
 if test -n "$JIGDOFALLBACKURLS"; then
     for url in "$JIGDOFALLBACKURLS"
     do
+        echo "$url" >> $jigdo
+    done
+fi
+
+# Snapshot URL - use last
+if [ "$snapurl"x != ""x ] ; then
     # The --try-last switch assigns a lower priority to the URL,
     # so it will only be used if other server entries (without the
     # --try-last) have already been tried without success.
-        echo "$url --try-last" >> $jigdo
-    done
+    echo "$snapurl --try-last" >> $jigdo
 fi
 
 # Create a snapshot tree if we've been told where to create one