remote-hg: always normalize paths

Apparently Mercurial can have paths such as 'foo//bar', so normalize all
paths.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Felipe Contreras

contrib/remote-helpers/git-remote-hg

@@ -260,6 +260,7 @@ class Parser:
         return (user, int(date), -tz)
 
 def fix_file_path(path):
+    path = os.path.normpath(path)
     if not os.path.isabs(path):
         return path
     return os.path.relpath(path, '/')