libosmo-mgcp: Connection Identifiers are allocated by MGW, not CA

The MGCP connection identifier is allocated by the MGW while processing
the CRCX, see RFC3435 2.1.3.2:. Including/Accepting a connection
identifier in CRCX is "forbidden" as per RFC3435 Section 3.2.2.

So the MGW side must *reject* a CRCX message with 'I' parameter, and
allocate a connection identifier which is subsequently returned in the
response.

Closes: OS#2648
Change-Id: Iab6a6038e7610c62f34e642cd49c93d11151252c
diff --git a/TODO-RELEASE b/TODO-RELEASE
index 917c995..9d0e0dc 100644
--- a/TODO-RELEASE
+++ b/TODO-RELEASE
@@ -23,5 +23,7 @@
 # If any interfaces have been added since the last public release, a++;
 # If any interfaces have been removed or changed since the last public release, a=0.
 #
-#library	what		description / commit summary line
-libosmo-mgcp	API/ABI change	parse and represent connection identifiers as hex strings
\ No newline at end of file
+#library		what		description / commit summary line
+libosmo-mgcp		API/ABI change	parse and represent connection identifiers as hex strings
+libosmo-mgcp		API/ABI change	connection identifiers are assigned by the server, not CA
+libosmo-mgcp-client	API/ABI change	parse and store connection identifier in response
\ No newline at end of file