Better certfile location detection by the test suite

test/ejabberd_SUITE.erl

@@ -37,6 +37,8 @@ init_per_suite(Config) ->
     SASLPath = filename:join([PrivDir, "sasl.log"]),
     MnesiaDir = filename:join([PrivDir, "mnesia"]),
     CertFile = filename:join([DataDir, "cert.pem"]),
+    {ok, CWD} = file:get_cwd(),
+    {ok, _} = file:copy(CertFile, filename:join([CWD, "cert.pem"])),
     application:set_env(ejabberd, config, ConfigPath),
     application:set_env(ejabberd, log_path, LogPath),
     application:set_env(sasl, sasl_error_logger, {file, SASLPath}),

test/ejabberd_SUITE_data/ejabberd.cfg

@@ -1,6 +1,6 @@
 {loglevel, 4}.
 {hosts, ["localhost"]}.
-{define_macro, 'CERTFILE', "../../test/ejabberd_SUITE_data/cert.pem"}.
+{define_macro, 'CERTFILE', "cert.pem"}.
 {listen,
  [
   {5222, ejabberd_c2s, [