Fixed tool name.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@7864 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/exp-drd/docs/README.txt b/exp-drd/docs/README.txt
index 240bdef..0ed0098 100644
--- a/exp-drd/docs/README.txt
+++ b/exp-drd/docs/README.txt
@@ -225,7 +225,7 @@
 How to use DRD
 --------------
 
-To use this tool, specify --tool=drd on the Valgrind command line.
+To use this tool, specify --tool=exp-drd on the Valgrind command line.
 
 
 Interpreting DRD's data race reports