Fix exit README.
-Test `restart`
+Test `exit`
====================
-This tests whether a process can restart. It calls printf, waits, then
-restarts. If it runs correctly you should see the same text printed
-multiple times.
+This tests whether a process can exit. It calls printf, waits, then
+exits. If the test is successful you should see
+
+Testing exit.
+Exiting.
+
+If exit does not succeed (the call returns), you should see
+
+Testing exit.
+Exiting.
+SHOULD NOT BE PRINTED.
+
