Race on push about weblate HOT 2 CLOSED

This is also related to issue #25, in case git operations would be handled in background, it would prevent such races, but on the other side it would make harder to give user feedback (without some ajax polling).

from weblate.

Again:

Traceback (most recent call last):

File "/usr/lib/python2.7/dist-packages/django/core/handlers/base.py", line 111, in get_response
response = callback(request, _callback_args, *_callback_kwargs)

File "/usr/lib/python2.7/dist-packages/django/contrib/auth/decorators.py", line 20, in _wrapped_view
return view_func(request, _args, *_kwargs)

File "/usr/lib/python2.7/dist-packages/django/contrib/auth/decorators.py", line 20, in _wrapped_view
return view_func(request, _args, *_kwargs)

File "/var/lib/django/l10n/weblate/trans/views.py", line 420, in push_project
if obj.do_push(request):

File "/var/lib/django/l10n/weblate/trans/models.py", line 133, in do_push
ret &= s.do_push(request)

File "/var/lib/django/l10n/weblate/trans/models.py", line 291, in do_push
if not self.do_update(request):

File "/var/lib/django/l10n/weblate/trans/models.py", line 277, in do_update
ret = self.update_branch(request)

File "/var/lib/django/l10n/weblate/trans/models.py", line 325, in update_branch
gitrepo.remotes.origin.update()

File "/usr/lib/python2.7/dist-packages/git/remote.py", line 510, in update
self.repo.git.remote("update", self.name)

File "/usr/lib/python2.7/dist-packages/git/cmd.py", line 227, in
return lambda _args, *_kwargs: self._call_process(name, _args, *_kwargs)

File "/usr/lib/python2.7/dist-packages/git/cmd.py", line 456, in _call_process
return self.execute(call, **_kwargs)

File "/usr/lib/python2.7/dist-packages/git/cmd.py", line 377, in execute
raise GitCommandError(command, status, stderr_value)

GitCommandError: 'git remote update origin' returned exit status 1: fatal: Unable to create '/var/lib/django/l10n/weblate/repos/weblate/master/.git/refs/remotes/origin/master.lock': File exists.

If no other git process is currently running, this probably means a
git process crashed in this repository earlier. Make sure no other git
process is running and remove the file manually to continue.
error: Could not fetch origin

from weblate.