fix usage text

This commit was SVN r2057.

test/include/run_tests

@@ -26,7 +26,7 @@ else if ("$1" == "atomic") then
   ./atomic
 else
   echo "correct use: "
-  echo "    run_tests (to run all class tests)"
+  echo "    run_tests (to run all include tests)"
   echo "or  run_tests <atomic>"
   exit -1
 endif