http weirdness, part deux

[jrcheli]

#787 documented a few issues seen with "apt get" and "apt install" commands. These use http/1 pipelining, a feature which broke our existing design where we expected requests and responses to be serially issued.

#809 made a set of changes which vastly improved but did not 100% resolve the resulting issue of corrupted http_method values.

This ticket is being opened to see what we can do to understand (and ideally address) these last, remaining http_method values.

[jrcheli]

@abetones, just tagging you here because I think we'll want to mention this as a known issue in 1.0.2...