git p4: disable read-only attribute before deleting
On windows, p4 marks un-edited files as read-only. Not only are
they read-only, but also they cannot be deleted. Remove the
read-only attribute before deleting in both the copy and rename
cases.
This also happens in the RCS cleanup code, where a file is marked
to be deleted, but must first be edited to remove adjust the
keyword lines. Make sure it is editable before patching.
Signed-off-by: Pete Wyckoff <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>