checkout: drop 'checkout_opts' dependency from prepare_linked_checkout
checkout: drop 'checkout_opts' dependency from prepare_linked_checkout

The plan is to relocate "git checkout --to" functionality to "git
worktree add", however, worktree.c won't have access to the 'struct
checkout_opts' passed to prepare_linked_worktree(), which it consults
for the pathname of the new worktree and the argv[] of the command it
should run to populate the new worktree. Facilitate relocation of
prepare_linked_worktree() by instead having it accept the pathname and
argv[] directly, thus eliminating the final references to 'struct
checkout_opts'.

Signed-off-by: Eric Sunshine <8d6e34f987851aa599257d3831a1af040886842f@sunshineco.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git