added registrar module modparam to limit maximum number of contacts

etc/ser-oob.cfg

@@ -296,11 +296,12 @@ modparam("registrar", "max_expires", 600)
 # for a shorter time than this
 modparam("registrar", "min_expires", 240)
 
-
 # identify natted contacts using a flag
 modparam("registrar", "load_nat_flag", "FLAG_NAT")
 modparam("registrar", "save_nat_flag", "FLAG_NAT")
 
+# maximum number of contacts
+modparam("registrar", "max_contacts", 10)
 
 # -- auth params --
 #modparam("auth_db", "calculate_ha1", yes)