sshpeer: remove frivolous call to _cleanup() _validaterepo() is called once during __init__. _cleanup() no-ops if the self._pipe* attributes aren't set. These attributes are set during _validaterepo(). So the call to _cleanup() isn't necessary. But just to be on the safe side, we add an assertion. Differential Revision: https://phab.mercurial-scm.org/D2030

sshpeer: extract pipe cleanup logic to own function So it can be used outside of instantiated classes. This is needed to support pipe creation before __init__ is called. Differential Revision: https://phab.mercurial-scm.org/D2029

sshpeer: move ssh command and repo creation logic out of __init__ It was easier to move both of these at once because repository creation requires various variables and I didn't want to add tons of arguments and code to __init__ that will soon be deleted anyway. We do add an extra argument so we can proxy values to the _validaterepo() call. But this is minimally invasive. Some callers of self._abort() were converted to just raise. Like before, the _abort() call wasn't necessary because self._pipe* aren't populated this early in the object's lifetime. As part of this, various private attributes derived from the parsed URL are no longer used. So we no longer set them. Differential Revision: https://phab.mercurial-scm.org/D2028