Fixed order of semaphore call stack and semaphore first observed call stack printing.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@8343 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/exp-drd/drd_error.c b/exp-drd/drd_error.c
index 72e7817..4c60c06 100644
--- a/exp-drd/drd_error.c
+++ b/exp-drd/drd_error.c
@@ -235,8 +235,8 @@
                  "%s: semaphore 0x%lx",
                  VG_(get_error_string)(e),
                  sei->semaphore);
-    first_observed(sei->semaphore);
     VG_(pp_ExeContext)(VG_(get_error_where)(e));
+    first_observed(sei->semaphore);
     break;
   }
   case BarrierErr: {