4g: add overlay template path for all suites

this allows, without changing the test case, to use a custom
template, which is useful for development. By default, nothing changes
and the OGT template is used

Change-Id: Ifc43ac41b16813116f2559da5223a6fecc186125
diff --git a/sysmocom/suites/4g/iperf3_ul.py b/sysmocom/suites/4g/iperf3_ul.py
index 6c0d25d..e243774 100755
--- a/sysmocom/suites/4g/iperf3_ul.py
+++ b/sysmocom/suites/4g/iperf3_ul.py
@@ -1,5 +1,10 @@
 #!/usr/bin/env python3
 from osmo_gsm_tester.testenv import *
+import os
+
+# Overlay suite-specific templates folder if it exists
+if os.path.isdir(os.path.join(os.path.dirname(__file__), 'templates')):
+  tenv.set_overlay_template_dir(os.path.join(os.path.dirname(__file__), 'templates'))
 
 epc = tenv.epc()
 enb = tenv.enb()