Factor out the code that marks a cache entry as matched for checkout
into a separate function. We are going to introduce a new mode in
'git checkout' in a subsequent commit, that is going to have a
slightly different logic. This would make this code unnecessarily
complex.
Moving that complexity into separate functions will make the code in
the subsequent step easier to follow.
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>