Bug 1561632 - Back out bug 1554987. r=ahal

Bug 1554987 made `mach try` use a transient remote, but that causes
problems with existing setups that happen to use the same remote name,
because of a combination of not-quite-as-documented-as-it-should
behavior of git.

- `git -c foo.bar=qux` doesn't override the value of `foo.bar` from the
  git configuration when `foo.bar` is an item that can take several
  values.
- `remote.$remote.url` and `remote.$remote.pushurl` take several values,
  allowing to give several URLs.

The combination of both means that if the git configuration already has
`remote.try.url` set, that value takes precedence (because git push
tries them one after the other, and takes the one from the command line
last)

One way we could increase the chances of things working out fine would
be to use `remote.try.pushurl`, which if already set, is more likely to
be right than an existing `remote.try.url`.

OTOH, it turns out, after more investigation, that bug 1554987 requires
a footgunny setup to happen in the first place. Namely, it requires
having run `git lfs install` from a git-cinnabar clone.

so we just go back to the previous status quo.

Differential Revision: https://phabricator.services.mozilla.com/D36149

python/mozversioncontrol/mozversioncontrol/__init__.py

@@ -478,11 +478,7 @@ class GitRepository(Repository):
 
         self._run('-c', 'commit.gpgSign=false', 'commit', '--allow-empty', '-m', message)
         try:
-            subprocess.check_call((self._tool,
+            subprocess.check_call((self._tool, 'push', 'hg::ssh://hg.mozilla.org/try',
-                                   '-c',
-                                   'remote.try.url=hg::ssh://hg.mozilla.org/try',
-                                   'push',
-                                   'try',
                                    '+HEAD:refs/heads/branches/default/tip'), cwd=self.path)
         finally:
             self._run('reset', 'HEAD~')

python/mozversioncontrol/test/test_push_to_try.py

@@ -40,8 +40,8 @@ def test_push_to_try(repo, monkeypatch):
             (tool, 'cinnabar', '--version'),
             (tool, '-c', 'commit.gpgSign=false', 'commit', '--allow-empty',
                    '-m', commit_message),
-            (tool, '-c', 'remote.try.url=hg::ssh://hg.mozilla.org/try',
+            (tool, 'push', 'hg::ssh://hg.mozilla.org/try',
-                   'push', 'try', '+HEAD:refs/heads/branches/default/tip'),
+                   '+HEAD:refs/heads/branches/default/tip'),
             (tool, 'reset', 'HEAD~'),
         ]