i18n: use "encoding.lower()" to normalize string in hgweb search query

some problematic encoding (e.g.: cp932) uses ASCII alphabet characters
in byte sequence of multi byte characters.

"str.lower()" on such byte sequence may treat distinct characters as
same one, and cause unexpected log matching.

this patch uses "encoding.lower()" instead of "str.lower()" to
normalize strings for compare.

mercurial/hgweb/webcommands.py

@@ -124,7 +124,8 b' def _search(web, req, tmpl):'
 
     def changelist(**map):
         count = 0
-        qw = query.lower().split()
+        lower = encoding.lower
+        qw = lower(query).split()
 
         def revgen():
             for i in xrange(len(web.repo) - 1, 0, -100):
@@ -139,9 +140,9 b' def _search(web, req, tmpl):'
         for ctx in revgen():
             miss = 0
             for q in qw:
-                if not (q in ctx.user().lower() or
-                        q in ctx.description().lower() or
-                        q in " ".join(ctx.files()).lower()):
+                if not (q in lower(ctx.user()) or
+                        q in lower(ctx.description()) or
+                        q in lower(" ".join(ctx.files()))):
                     miss = 1
                     break
             if miss: