Set default push strategy for git

Fixes #607
Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/trans/vcs.py

@@ -369,6 +369,13 @@ class GitRepository(Repository):
         '''
         self._popen(['init', self.path])
 
+    def check_config(self):
+        """
+        Checks VCS configuration.
+        """
+        # We directly set config as it takes same time as reading it
+        self.set_config('push.default', 'simple')
+
     @classmethod
     def clone(cls, source, target, bare=False):
         """