Respect the default comment/ping status for new posts even when someone has...

Respect the default comment/ping status for new posts even when someone has hidden the meta box which lets you alter them on a per-post basis.
Fixes #13473 props solarissmoke. 


git-svn-id: https://core.svn.wordpress.org/trunk@19372 1a063a9b-81f0-0310-95a4-ce76da25c4cd