Update text=auto / core.autocrlf=false behavior

Git for Windows 1.9.4 changed the behavior when the text=auto
attribute is specified and core.autocrlf=false.  Previous observed
behavior would *not* filter files when going into the working
directory, the new behavior *does* filter.  Update our behavior to match.
Merge pull request #2435 from ethomson/text_attr

Update text=auto / core.autocrlf=false behavior