Add phosphor collection to cbcollect_info
Add phosphor collection to cbcollect_info

Records the contents of the trace ring buffer from memcached, writing
to kv_trace.json.

This can be viewed using the built-in trace viewer in Chrome -
chrome://tracing

Change-Id: Ice6e1e4e496a711417100bcb64b424298cfaffc9
Reviewed-on: http://review.couchbase.org/80600
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>
Tested-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server