X It was incorrect to use the same loopback address for enb.gtp and core.gtp

Original SR had defaults as

mme.gtp: 127.0.1.100
enb.gtp: 127.0.1.1

With this both can listen at the same port and talk to each other.

But if we set gtp addr to be the same for mme and enb, then enb listen
will fail as the listening address is already taken by mme.

Fix it with restoring explicit enb gtp loopback default.

software/ors-amarisoft/config/enb.jinja2.cfg

@@ -197,7 +197,7 @@
 {%-     do vip.append(_)  %}
 {%-   endfor  %}
 {%-   if len(vip) > 0  and  all(vip |map(attribute='islo')) %}
-  gtp_addr: "{{ vip[0].ip }}",
+  gtp_addr: "{{ gtp_addr_lo }}",
 {%-   else  %}
 {#-     core is external - use external ipv4/ipv6 #}
 {%-     if slapparameter_dict.use_ipv4  %}

software/ors-amarisoft/instance-enb.jinja2.cfg

@@ -8,6 +8,7 @@
   'use_ipv4':     False,
   'nssai':        {'1': {'sst': 1}}
 } %}
+{%- set gtp_addr_lo = '127.0.1.1' %}
 {%- for k,v in enb_defaults|dictsort %}
 {%-   do slapparameter_dict.setdefault(k, v) %}
 {%- endfor %}
@@ -194,6 +195,7 @@ context =
   key slapparameter_dict myslap:parameter_dict
   raw gtp_addr_v6 {{ my_ipv6 }}
   raw gtp_addr_v4 {{ lan_ipv4 }}
+  raw gtp_addr_lo {{ gtp_addr_lo }}
   import  xbuildout xbuildout
   import  netaddr netaddr
   ${:extra-context}