amarisoft_{mme,enb}: make sure mcc/mnc are zero padded

same as for srsEPC this is also required for Amarisoft MME and eNB to support, i.e. 001/01

Note that the 3 digit MNC isn't covered by this.

Change-Id: I80a84e01ec9530c285634452d7c18c17bdd595ce
diff --git a/src/osmo_gsm_tester/templates/amarisoft_ltemme.cfg.tmpl b/src/osmo_gsm_tester/templates/amarisoft_ltemme.cfg.tmpl
index fb3ec98..3c83bed 100644
--- a/src/osmo_gsm_tester/templates/amarisoft_ltemme.cfg.tmpl
+++ b/src/osmo_gsm_tester/templates/amarisoft_ltemme.cfg.tmpl
@@ -39,7 +39,7 @@
 
   s1ap_bind_addr: "${epc.run_addr}",
 
-  plmn: "${epc.mcc}${epc.mnc}",
+  plmn: "${'{0:03}'.format(int(epc.mcc))}${'{0:02}'.format(int(epc.mnc))}",
   mme_group_id: 32769,
   mme_code: 1,