t0027: add tests for eol without text in .gitattributes

t0027: add tests for eol without text in .gitattributes

Right now, it isn't clear what the behavior is when the eol attribute is
set in .gitattributes but the text attribute is not.  Let's add some
tests to document this behavior in our code, which happens to be that
the behavior is as if we set the text attribute implicitly.  This will
make sure we don't accidentally change the behavior, which somebody is
probably relying on, and serve as documentation to developers.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>