[PATCH 5 of 6 foldmap-in-C V2] encoding.upper: factor out fallback code

[Siddharth Agarwal]

# HG changeset patch
# User Siddharth Agarwal <sid0 at fb.com>
# Date 1427873441 25200
#      Wed Apr 01 00:30:41 2015 -0700
# Node ID e8023e64800c8a009eac62cfc37cc7d39484b282
# Parent  29fdd81a2553fb8e4a493ee2706bd7a22df890d0
encoding.upper: factor out fallback code

This will be used as the fallback function on Windows.

diff --git a/mercurial/encoding.py b/mercurial/encoding.py
--- a/mercurial/encoding.py
+++ b/mercurial/encoding.py
@@ -338,7 +338,9 @@ def upper(s):
     try:
         return asciiupper(s)
     except UnicodeDecodeError:
-        pass
+        return upperfallback(s)
+
+def upperfallback(s):
     try:
         if isinstance(s, localstr):
             u = s._utf8.decode("utf-8")