sshpeer: establish SSH connection before class instantiation We want to move the handshake to before peers are created so we can instantiate a different peer class depending on the results of the handshake. This necessitates moving the SSH process invocation to outside the peer class. As part of the code move, some variables were renamed for clarity. util.popen4() returns stdin, stdout, and stderr in their typical file descriptor order. However, stdin and stdout were being mapped to "pipeo" and "pipei" respectively. "o" for "stdin" and "i" for "stdout" is a bit confusing. Although it does make sense for "output" and "input" from the perspective of the client. But in the context of the new function, it makes sense to refer to these as their file descriptor names. In addition, the last use of self._path disappeared, so we stop setting that attribute and we can delete the redundant URL parsing necessary to set it. Differential Revision: https://phab.mercurial-scm.org/D2031