kill-old-processes fix

kill.patch

diff --git a/Tools/BuildSlaveSupport/kill-old-processes b/Tools/BuildSlaveSupport/kill-old-processes
index 880258d1c324..d831e3b5be45 100755
--- a/Tools/BuildSlaveSupport/kill-old-processes
+++ b/Tools/BuildSlaveSupport/kill-old-processes
@@ -180,7 +180,7 @@ def main(user=None):
         builddir_bin = "WebKitBuild/Release/bin" if os.path.isdir("WebKitBuild/Release/bin") else "WebKitBuild/Debug/bin"
         for task in tasksToKill + taskToKillUnix + listAllWebKitPrograms(builddir_bin):
             os.system("killall -9 -v " + task)
-        os.system("ps aux | grep -P '.+/python .+(run_webkit_tests|run-webkit-tests|mod_pywebsocket)' | grep -v grep | awk '{print $2}' | xargs kill")
+        os.system("ps aux | grep -P '.+/python .+(run_webkit_tests|run-webkit-tests|mod_pywebsocket)' | grep -v grep | awk '{print $2}' | xargs -r kill")
         removeOrphanShmSegments()
     else:
         sys.exit()