revlog: zlib.error sent to the user (issue3424)

revlog: zlib.error sent to the user (issue3424)

Give the user the zlib error message instead of a backtrace when decompression
fails.

--- a/mercurial/revlog.py	Sun Jun 03 19:35:45 2012 +0200
+++ b/mercurial/revlog.py	Mon Jun 04 14:46:42 2012 -0700
@@ -112,7 +112,10 @@
     if t == '\0':
         return bin
     if t == 'x':
-        return _decompress(bin)
+        try:
+            return _decompress(bin)
+        except zlib.error, e:
+            raise RevlogError(_("revlog decompress error: %s") % str(e))
     if t == 'u':
         return bin[1:]
     raise RevlogError(_("unknown compression type %r") % t)