don't build after failed, unless there's been a modification!

releng.control/cc_config.xml

@@ -56,7 +56,7 @@
     </plugin>
     <plugin
         name="project"
-        buildafterfailed="true">
+        buildafterfailed="false">
         <dateformat
             format="yyyy-MM-dd HH:mm '('z')'" />
         <log
@@ -110,7 +110,7 @@
         The next criteria is importance
         
     -->
-    <project
+    <project requireModification="false"
         name="cleanup-artifacts-B">
         <schedule
             interval="${time.oneHour}">