Revert "commands: Always put ship or land unit before retreating it"

Revert "commands: Always put ship or land unit before retreating it"

This reverts commit f4d8d64bb34dee75cb2485c130e125fdd3980c18.

Breaks retreat after ship got sunk by bombs or missile.

ship_bomb() and launch_missile() pass .shp_own to retreat_ship().
Wrong after putship(), because putship() resets the owner when the
ship got sunk.  retreat_ship() then oopses and fails to retreat the
surviving members of the group.

Other callers save the owner before putting the ship, and pass that.
We could change these two to do the same.  But since we're trying to
get a release out, simply revert the broken commit instead.