ssh: capture output with bundle2 again (issue4642)

I just discovered that we are not displaying ssh server output in real time
anymore. So we can just fall back to the bundle2 output capture for now. This
fix the race condition issue we where seeing in tests. Re-instating real time
output for ssh would fix the issue too but lets get the test to pass first.

mercurial/exchange.py

@@ -1288,7 +1288,7 b' def unbundle(repo, cg, heads, source, ur'
     # quick fix for output mismatch with bundle2 in 3.4
     captureoutput = repo.ui.configbool('experimental', 'bundle2-output-capture',
                                        False)
-    if url.startswith('remote:http:') or url.startswith('remote:https:'):
+    if url.startswith('remote:'):
         captureoutput = True
     try:
         check_heads(repo, heads, 'uploading changes')

tests/test-bundle2-exchange.t

@@ -694,7 +694,6 b' Check output capture control.'
   $ hg -R main push ssh://user@dummy/other -r e7ec4e813ba6
   pushing to ssh://user@dummy/other
   searching for changes
-  abort: pretxnchangegroup hook exited with status 1
   remote: adding changesets
   remote: adding manifests
   remote: adding file changes
@@ -703,6 +702,7 b' Check output capture control.'
   remote: transaction abort!
   remote: Cleaning up the mess...
   remote: rollback completed
+  abort: pretxnchangegroup hook exited with status 1
   [255]
   $ hg -R main push http://localhost:$HGPORT2/ -r e7ec4e813ba6
   pushing to http://localhost:$HGPORT2/