Update bug tracker URL

Change all instances of bugzilla.gnome.org to bugs.gnucash.org, reflecting
our migration to a self-hosted bug tracker.

Inform the Translation Project Coordinator at release that this affects
translatable strings and that all message catalogs have been updated.

libgnucash/engine/test/test-numeric.cpp

@@ -720,7 +720,7 @@ check_mult_div (void)
                      a, b, "expected %s got %s = %s * %s for div 100th's");
 
     /* Check for math with 2^63 < num*num < 2^64 which previously failed
-     * see http://bugzilla.gnome.org/show_bug.cgi?id=144980
+     * see http://bugs.gnucash.org/show_bug.cgi?id=144980
      */
     v = 1000000;
     a = gnc_numeric_create(1 * v, v);