XML-RPC publish ignores publicize_checkbox_default = false.

## Issue

In the last week or two, I've noticed a big problem with posting via IFTTT and Publicize not respecting publicize_checkbox_default = false.

When IFTTT posts something, Publicize will still post to all connected accounts despite setting it to false. When posting via Wordpress directly, it does not auto-publicize.
## Testing

Attempted XML-RPC posting with a Blogsy iPad blogging app to see if this was repeatable. When posting with Blogsy, Publicize still posts to all networks despite setting the default to false.

This is a recent issue in the last week or two. Not exactly sure when. Current versions as follows.
## Suspects

I suspect the fix for #314 inadvertently causes this issue.
## Versions

WP 3.8.1
JetPack 2.9.2
Theme: Syntax 1.0.1 (Actually running a child theme. Putting override code in parent function.php has no effect)