Pay later contributions default status to completed

To reproduce the problem (reproduced on the demo site) :

• create a contribution page with pay later option but not
• don't check "Execute real-time monetary transactions" but check "Pay later option"
• go to live transaction page, the Pay later option is checked by default which is correct
• after confirming, go see the contribution - the status is "Completed" which is wrong - it should be "Pending (Pay Later)"