[meld] Teach git support about .git as a file (closes bgo#589640)

[Kai Willadsen <kaiw src gnome org>]

commit 2a5a309ffd3a215ca99e53a2c0d6ba99761e7f2d
Author: Geoffrey Irving <irving naml us>
Date:   Fri Jul 24 14:49:45 2009 -0400

    Teach git support about .git as a file (closes bgo#589640)
    
    Instead of being a directory, .git can be a file containing "gitdir: ...",
    so replace os.path.isdir with os.path.exists.

 meld/vc/git.py |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/meld/vc/git.py b/meld/vc/git.py
index 3f51e22..833b9b2 100644
--- a/meld/vc/git.py
+++ b/meld/vc/git.py
@@ -47,6 +47,12 @@ class Vc(_vc.CachedVc):
         "unmerged":   _vc.STATE_CONFLICT,
     }
 
+    def check_repo_root(self, location):
+        # Check exists instead of isdir, since .git might be a git-file
+        if not os.path.exists(os.path.join(location, self.VC_DIR)):
+            raise ValueError
+        return location
+
     def commit_command(self, message):
         return [self.CMD,"commit","-m",message]
     def diff_command(self):