When checking out a repository the default behaviour is to abort if
local changes are present. If the new `--force-checkout` argument is
passed on the command line then any local changes will instead be
discarded so that the desired refspec can be checked out.
Signed-off-by: Paul Barker <pbarker@konsulko.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>