Unset the HOME env before calling git binary

If we do no unset the env, git will use a potential
.gitconfig which can alter results

src/Gitonomy/Git/Repository.php

@@ -439,6 +439,8 @@ protected function getProcess($command, $args = array())
 
         $builder = new ProcessBuilder(array_merge($base, $args));
 
+        $builder->inheritEnvironmentVariables(false);
+
         return $builder->getProcess();
     }
 }