Provide Channel for Ringpop

[mantas-sidlauskas]

What changed?
RPC factory provides Tchannel Channel

Why?
Ringpop doesn't need dispatcher anymore. Channel is retrieved from RPC factory without interface assertion

How did you test it?
Unit tests

Potential risks

Release notes

Documentation Changes

[coveralls]

Pull Request Test Coverage Report for Build a5a98f32-f4d2-4b2c-bfd3-8330789688fe

• 4 of 15 (26.67%) changed or added relevant lines in 3 files are covered.
• 30 unchanged lines in 11 files lost coverage.
• Overall coverage increased (+0.05%) to 56.834%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
common/rpc/factory.go	2	5	40.0%
cmd/server/cadence/server.go	0	4	0.0%
common/config/ringpop.go	2	6	33.33%

Files with Coverage Reduction	New Missed Lines	%
service/history/execution/mutable_state_task_refresher.go	1	73.82%
client/history/client.go	2	40.32%
client/history/metricClient.go	2	45.94%
common/task/fifoTaskScheduler.go	2	84.54%
common/task/parallelTaskProcessor.go	2	92.75%
common/task/weightedRoundRobinTaskScheduler.go	2	88.6%
service/history/handler.go	2	48.32%
service/history/task/priority_assigner.go	2	89.74%
service/matching/matcher.go	2	91.46%
service/frontend/workflowHandler.go	4	58.59%

Totals
Change from base Build f3e4a4d4-c5e9-4a4c-9dbb-e9f3d64d0955:	0.05%
Covered Lines:	81641
Relevant Lines:	143648

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💛 - Coveralls