utils: fixed sinitiser error

[root@localhost]# kamcmd cfg.seti param_group param_name value

=================================================================
==2409977==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 38 byte(s) in 1 object(s) allocated from:
    #0 0xffff98c250af in malloc (/lib64/libasan.so.5+0xd50af)
    #1 0x41549f in parse_listen_id /root/kamailio/utils/kamcmd/parse_listen_id.c:133
    #2 0x4144fb in main /root/kamailio/utils/kamcmd/kamcmd.c:2075
    #3 0xffff97dc0de3 in __libc_start_main (/lib64/libc.so.6+0x20de3)
    #4 0x40260b  (/usr/local/sbin/kamcmd+0x40260b)

utils/kamcmd/kamcmd.c

@@ -2106,6 +2106,7 @@ int main(int argc, char** argv)
 			fprintf(stderr, "ERROR: Bad socket type for %s\n", sock_name);
 			goto error;
 	}
+	free(sock_id->buf); /* not needed anymore */
 	free(sock_id); /* not needed anymore */
 	sock_id=0;