registrar: save() returns new err code

- return err code on too many entries for AOR

src/modules/registrar/README

@@ -856,7 +856,8 @@ modparam("registrar", "contact_max_size", 500)
        be a dynamic string with pseudo-variables.
 
    Return codes:
-     * -1 - error.
+     * -2 - error, too many contacts for AOR.
+       -1 - error.
        1 - contacts inserted.
        2 - contacts updated.
        3 - contacts deleted.

src/modules/registrar/doc/registrar_admin.xml

@@ -1029,6 +1029,9 @@ modparam("registrar", "contact_max_size", 500)
 		<para>Return codes:</para>
 		<itemizedlist>
 		<listitem>
+			<para>
+			<emphasis>-2</emphasis> - error, too many contacts for AOR.
+			</para>
 			<para>
 			<emphasis>-1</emphasis> - error.
 			</para>

src/modules/registrar/save.c

@@ -1007,7 +1007,9 @@ error:
 	update_stat(rejected_registrations, 1);
 	if (is_route_type(REQUEST_ROUTE) && !is_cflag_set(REG_SAVE_NORPL_FL) )
 		reg_send_reply(_m);
-
+    if (R_TOO_MANY == rerrno)
+	    return -2; 
+	/* for all other */
 	return 0;
 }