When no LCD display is attached AND when printing from SD card, go ahead...

... and call sdcard::finishPlayback() so that sdcard::isPlaying() will return false and the host state will return to HOST_STATE_READY rather then remain at HOST_STATE_BUILDING_FROM_SD.  When there is an LCD display, we prefer to stay at H_S_B_FROM_SD so that the user has a chance to 'print another'.