Missing match informations in default pjsip.identify.conf

Default pjsip.identify.conf has type=identify but no 'match=' or 'match_header=' fields.
This was accepted till Asterisk 13.22, but since 13.23 it's illegal.
The consequence are:

• pjsip show identifies doesn't shows endpoints
• error displayed:

[2019-03-12 09:10:01] ERROR[31298]: res_pjsip_endpoint_identifier_ip.c:440 ip_identify_apply: Identify '209-identify' is not configured to match anything.
[2019-03-12 09:10:01] ERROR[31298]: res_sorcery_config.c:409 sorcery_config_internal_load: Could not create an object of type 'identify' with id '209-identify' from configuration file 'pjsip.conf'

• example of no more accepted configuration:

[2000-identify]
type=identify
endpoint=2000

• example of working configuration:

[2000-identify]
type=identify
endpoint=2000
match=192.168.1.5

[2001-identify]
type=identify
endpoint=2001
match_header=sip:2001

See also https://issues.asterisk.org/jira/browse/ASTERISK-28327