Fix bug #22306: move_unit moves a unit even when it shouldn't

Modified the lua script for wml_action.move_unit. In the
loop to check for vacant tile, if the current location
is equal to the previous location we don't look for a
vacant tile since our location is free (where we are).
fix whitespace at end of line
Merge branch 'moveunitbug_fixup'

Conflicts:
	changelog