[PATCH 2 of 4] error: derive RevlogError from HintException instead of Exception

[Jordi Gutiérrez Hermoso]

# HG changeset patch
# User Jordi Gutiérrez Hermoso <jordigh at octave.org>
# Date 1432239634 14400
#      Thu May 21 16:20:34 2015 -0400
# Node ID 88b99c48761cc7b982b84294aa679b63f5edf967
# Parent  1afb582cf7f85118a1c48c69aaa54625db5afab0
error: derive RevlogError from HintException instead of Exception

This will allow us to now pass hints into this exception.

diff --git a/mercurial/error.py b/mercurial/error.py
--- a/mercurial/error.py
+++ b/mercurial/error.py
@@ -18,7 +18,7 @@ class HintException(Exception):
         Exception.__init__(self, *args)
         self.hint = kw.get('hint')
 
-class RevlogError(Exception):
+class RevlogError(HintException):
     pass
 
 class FilteredIndexError(IndexError):