sshpeer: inline I/O into _validaterepo() We want to move the handshake code out of the peer class so the peer factory function can perform the handshake and instantiate a proper class depending on the results. To make that refactor easier to read, we first inline I/O functionality into _validaterepo(). Test output for low-level protocol tests didn't change, thus hopefully demonstrating that this refactor didn't change any material behavior. Because we no longer call _callstream(), our test extension for monkeypatching the peer had to change its hook point. Differential Revision: https://phab.mercurial-scm.org/D2033