### Description

Hello,

related to #265 , I can reproduce the issue, with kamailio 4.4.6+jessie from kamailio debian repository

- 0x04 flag is set on save() - old contacts are deleted on the server receiving the REGISTER message - old contacts are not deleted on servers being notified via DMQ

<!-- Explain what you did, what you expected to happen, and what actually happened. -->

### Troubleshooting

#### Reproduction

- Setup 2 servers with dmq & dmq_usrloc replication between each other, and with registration on 1st - Use 0x04 flag on save() function - Register your softphones a 1st time on 1 server: registration is replicated on 2d server, contact is on both servers - Reregister (with different contact) on same server: - previous contact is deleted on 1st server - new contact is replicated to 2d server - previous contact is *NOT* delete on 2d server

#### Log Messages

server1 (REGISTER message):

DEBUG: usrloc [ucontact.c:1692]: update_ucontact(): exists callback for type= UL_CONTACT_UPDATE DEBUG: usrloc [ul_callback.h:84]: run_ul_callbacks(): contact=0x7f0096e0b548, callback type 2/15, id 0 entered DEBUG: dmq_usrloc [usrloc_sync.c:578]: dmq_ul_cb_contact(): Callback from usrloc with type=2 DEBUG: dmq_usrloc [usrloc_sync.c:548]: usrloc_dmq_send_contact(): sending serialized data {"action":1,"aor":"+33564093848","ruid":"uloc-5a86b8c5-31e0-2","c":"sip:+33564093848@xxx:41502;ob","received":"","path":"","callid":"ntoWjs3R3WpP9Z5rsi7Npmr2rRGKstls","user_agent":"CSipSimple_porridge-23/r2457","instance":"","expires":1518779539,"cseq":55952,"flags":0,"cflags":0,"q":-1,"last_modified":1518778639,"methods":8159,"reg_id":0} DEBUG: dmq_usrloc [usrloc_sync.c:299]: usrloc_dmq_send(): sending dmq broadcast...

server2 (DMQ recipient):

DEBUG: dmq_usrloc [usrloc_sync.c:327]: usrloc_dmq_handle_msg(): dmq message received from sip:usrloc@172.16.67.15:5060 DEBUG: dmq_usrloc [usrloc_sync.c:429]: usrloc_dmq_handle_msg(): Received DMQ_UPDATE. Update contact info... DEBUG: dmq_usrloc [usrloc_sync.c:64]: add_contact(): aor: +33564093848 DEBUG: dmq_usrloc [usrloc_sync.c:65]: add_contact(): ci->ruid: uloc-5a86b8c5-31e0-2 DEBUG: dmq_usrloc [usrloc_sync.c:66]: add_contact(): aorhash: -1799456359 DEBUG: dmq_usrloc [usrloc_sync.c:72]: add_contact(): Found contact DEBUG: usrloc [ucontact.c:1692]: update_ucontact(): exists callback for type= UL_CONTACT_UPDATE DEBUG: usrloc [ul_callback.h:84]: run_ul_callbacks(): contact=0x7f3900243bd0, callback type 2/15, id 0 entered DEBUG: dmq_usrloc [usrloc_sync.c:578]: dmq_ul_cb_contact(): Callback from usrloc with type=2 DEBUG: dmq_usrloc [usrloc_sync.c:600]: dmq_ul_cb_contact(): Contact received from DMQ... skip DEBUG: usrloc [ucontact.c:1004]: db_update_ucontact_ruid(): ruid:uloc-5a86b8c5-31e0-2 DEBUG: usrloc [ucontact.c:1133]: db_update_ucontact_ruid(): contact:sip:+33564093848@xxx:41502;ob DEBUG: dmq_usrloc [usrloc_sync.c:74]: add_contact(): Release record DEBUG: dmq_usrloc [usrloc_sync.c:76]: add_contact(): Unlock udomain

the recipient receive an UPDATE message only. according to usrloc_sync.c:usrloc_dmq_handle_msg(), UPDATE message add the new contact only (execute add_contact()), but the other one is not deleted

and there is no DMQ_RM message generated from the emitter

### Possible Solutions

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### Additional Information

``` version: kamailio 4.4.6 (x86_64/linux) flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. id: unknown compiled with gcc 4.9.2 ```

* **Operating System**:

``` 3.16.0-4-amd64 #1 SMP Debian 3.16.43-2+deb8u2 (2017-06-26) x86_64 GNU/Linux ```