Check for patches repo with os.path.isdir not os.path.exists

mercurial/util.py

@@ -1713,7 +1713,7 b' def walkrepos(path):'
             dirs[:] = [] # don't descend further
             yield root # found a repository
             qroot = os.path.join(root, '.hg', 'patches')
-            if os.path.exists(os.path.join(qroot, '.hg')):
+            if os.path.isdir(os.path.join(qroot, '.hg')):
                 yield qroot # we have a patch queue repo here
 
 _rcpath = None