icasefs: disuse length check against un-normcase()-ed filenames

this patch disuses length check against un-normcase()-ed filenames
gotten by "os.listdir()", because there is no assurance that
filesystem stores filenames normalized except in letter case, even
though some case insensitive filesystems (in some environment, for
some language setting) store them in such manner.

mercurial/util.py

@@ -622,9 +622,8 b' def fspath(name, root):'
     The root should be normcase-ed, too.
     '''
     def find(p, contents):
-        lenp = len(p)
         for n in contents:
-            if lenp == len(n) and normcase(n) == p:
+            if normcase(n) == p:
                 return n
         return None