reduce sync_timeout time to 4 seconds, a=chris

diff --git a/lib/index_bundle_iterators/intersect_iterator.php b/lib/index_bundle_iterators/intersect_iterator.php
index bd8210125..0ffefa0cc 100644
--- a/lib/index_bundle_iterators/intersect_iterator.php
+++ b/lib/index_bundle_iterators/intersect_iterator.php
@@ -113,7 +113,7 @@ class IntersectIterator extends IndexBundleIterator
      *  Number of seconds before timeout and stop
      *  syncGenDocOffsetsAmongstIterators if slow
      */
-    const SYNC_TIMEOUT = 5;
+    const SYNC_TIMEOUT = 4;

     /**
      * Creates an intersect iterator with the given parameters.