RFC Violation - 401 Unauthorized not sending WWW-Authenticate to SUBSCRIBE messages

[junction1153]

Describe the bug
Previously reported in ticket # 1779 but not addressed. When FS sends a 401 Unauthorized to a SUBSCRIBE request, the WWW-Authenticate string is missing. This is required per RFC RFC 3261 section 22.2

To Reproduce
Simply have an endpoint send a SUBSCRIBE for BLF. When the endpoint re-sends a subscribe after the sofia nonce expired, freeswitch will respond with 401 unauthorized

Expected behavior
WWW-Authenticate string should be received in the SIP message

Package version or git hash

• Tested with 1.10.8 to 1.10.12, all easily reproduceable

[greenbea]

I fixed this bug #2648