res_pjsip/location: Destroy contact_status objects on contact deletion

The contact_status Sorcery objects are currently not destroyed when a contact
is deleted. This causes the contact's last known RTT/status to be 'sticky'
when the contact itself may no longer exist. This patch causes the
contact_status objects associated with both dynamic and static contacts to
be destroyed if the AoR holding those contacts is also destroyed (or via
other paths where a contact may be deleted.)

Change-Id: I7feec8b9278cac3c5263a4c0483f4a0f3b62426e