bundle2: print "error:abort" message to stderr instead of stdout

It seems like the server's message is something you'd like to see even
with `--quiet`. It's clearly part of the error.

Differential Revision: https://phab.mercurial-scm.org/D9954

mercurial/exchange.py

@@ -1135,9 +1135,9 b' def _pushbundle2(pushop):'
         except error.BundleValueError as exc:
             raise error.Abort(_(b'missing support for %s') % exc)
         except bundle2.AbortFromPart as exc:
-            pushop.ui.status(_(b'remote: %s\n') % exc)
+            pushop.ui.error(_(b'remote: %s\n') % exc)
             if exc.hint is not None:
-                pushop.ui.status(_(b'remote: %s\n') % (b'(%s)' % exc.hint))
+                pushop.ui.error(_(b'remote: %s\n') % (b'(%s)' % exc.hint))
             raise error.Abort(_(b'push failed on remote'))
     except error.PushkeyFailed as exc:
         partid = int(exc.partid)
@@ -1832,7 +1832,7 b' def _pullbundle2(pullop):'
             op.modes[b'bookmarks'] = b'records'
             bundle2.processbundle(pullop.repo, bundle, op=op)
         except bundle2.AbortFromPart as exc:
-            pullop.repo.ui.status(_(b'remote: abort: %s\n') % exc)
+            pullop.repo.ui.error(_(b'remote: abort: %s\n') % exc)
             raise error.Abort(_(b'pull failed on remote'), hint=exc.hint)
         except error.BundleValueError as exc:
             raise error.Abort(_(b'missing support for %s') % exc)

tests/test-narrow-pull.t

@@ -147,6 +147,7 b' Can pull into repo with a single commit'
   $ hg clone -q --narrow ssh://user@dummy/master narrow2 --include "f1" -r 0
   $ cd narrow2
   $ hg pull -q -r 1
+  remote: abort: unexpected error: unable to resolve parent while packing b'00manifest.i' 1 for changeset 0
   transaction abort!
   rollback completed
   abort: pull failed on remote

tests/test-remotefilelog-clone-tree.t

@@ -91,7 +91,6 b''
 #   flakiness here
   $ hg clone --noupdate ssh://user@dummy/shallow full 2>/dev/null
   streaming all changes
-  remote: abort: Cannot clone from a shallow repo to a full repo.
   [255]
 
 # getbundle full clone

tests/test-remotefilelog-clone.t

@@ -85,9 +85,9 b' check its contents separately.'
   $ TEMP_STDERR=full-clone-from-shallow.stderr.tmp
   $ hg clone --noupdate ssh://user@dummy/shallow full 2>$TEMP_STDERR
   streaming all changes
-  remote: abort: Cannot clone from a shallow repo to a full repo.
   [255]
   $ cat $TEMP_STDERR
+  remote: abort: Cannot clone from a shallow repo to a full repo.
   abort: pull failed on remote
   $ rm $TEMP_STDERR