Remove connection pooling

[MatMeredith]

UTs run and tested in Kubernetes deployment. Don't think I understand the implications or the background to why we use connection pooling in Bono well enough to know if this is the right thing to do though.

We'd also have to retire the BonoConnectedSprouts table from the MIB if we were to merge this.

[MatMeredith]

@johadalin @AlexHockey FYI... Not clear whether we should be looking to merge at this time -- just wanted to see if it solved the Kubernetes issue...

[AlexHockey]

Does this cause Bono to do DNS lookups using the BaseResolver (good) or does it cause the resolution to happen in PJSIP (bad)?

[MatMeredith]

I don't fully understand the code, but from trace on a node with this patch...

02-10-2017 14:19:45.886 UTC Debug pjutils.cpp:474: Next hop node is encoded in top route header
02-10-2017 14:19:45.886 UTC Debug sipresolver.cpp:62: SIPResolver::resolve for name sprout.mgm.svc.cw-k8s.test, port 5052, transport 6, family 2
02-10-2017 14:19:45.886 UTC Debug utils.cpp:418: Attempt to parse sprout.mgm.svc.cw-k8s.test as IP address
02-10-2017 14:19:45.886 UTC Debug sipresolver.cpp:125: Port is specified
02-10-2017 14:19:45.886 UTC Debug sipresolver.cpp:293: Perform A/AAAA record lookup only, name = sprout.mgm.svc.cw-k8s.test
02-10-2017 14:19:45.886 UTC Verbose dnscachedresolver.cpp:468: Check cache for sprout.mgm.svc.cw-k8s.test type 1
02-10-2017 14:19:45.886 UTC Debug dnscachedresolver.cpp:474: No entry found in cache
02-10-2017 14:19:45.886 UTC Debug dnscachedresolver.cpp:477: Create cache entry pending query

I think that's what we want?

[MatMeredith]

@AlexHockey ^^

[AlexHockey]

Yep, looks good to me.

[johadalin]

Should this be merged down?