downgrade freeswitch

issues in production with `master` versions sending original INVITE extra-headers in re-INVITE, causing issues (`X-CCNQ3-Extra` causes failures due to fragmentation; `X-CCNQ3-MediaProxy: on` causes lack of mediaproxy rewrite on reINVITES SDP).
Added SIP warning.
debian: bump freeswitch version to installable one
test: freeswitch-release (initial)
test: initial attempt with sipp
test: no stats, no media
test: valid test-with-reinvite