fix osmo-stp.cfg: accept-asp-connections must be a child of listen m3ua

Change-Id: I266b129788b2caaec0f345f80a2c5eab0172bf97
diff --git a/src/osmo_gsm_tester/templates/osmo-stp.cfg.tmpl b/src/osmo_gsm_tester/templates/osmo-stp.cfg.tmpl
index ab41de9..eb6ac1d 100644
--- a/src/osmo_gsm_tester/templates/osmo-stp.cfg.tmpl
+++ b/src/osmo_gsm_tester/templates/osmo-stp.cfg.tmpl
@@ -13,4 +13,4 @@
 cs7 instance 0
  xua rkm routing-key-allocation dynamic-permitted
  listen m3ua 2905
- accept-asp-connections dynamic-permitted
+  accept-asp-connections dynamic-permitted