gitignore: ensure utest.cpp not ignored

Couldn't see test/utest.cpp in my Atom IDE. It doesn't show things that
match in the .gitignore file. Update the .gitignore to be specific on
what to ignore with the unit tests.

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: Ifbbabdadad9252ac1596194129a6f76a3d6a36ab
1 file changed