Speed up testing

Removed unnecessary sleeps from tests that appear to serve no
purpose. Moveed the kerberos code from the general startup routines to the
kerberos test.

maxscale-system-test/mxs922_restart.cpp

@@ -66,7 +66,7 @@ int main(int argc, char *argv[])
 
     test->tprintf("Restarting MaxScale");
     test->restart_maxscale();
-    sleep(10);
+    sleep(2);
 
     do_query(test, false);