[v4.4.2] Fix message size metrics
Fixed
Fix message size histogram updates (testillano/http2comm#29).
Also, redundant condition in command-line assignment for h2agent parameter.
Docker images
https://github.com/users/testillano/packages/container/package/h2agent
https://github.com/users/testillano/packages/container/package/h2agent_builder
https://github.com/users/testillano/packages/container/package/h2agent_training
Issues report
Fix message size histogram updates (testillano/http2comm#29).