Movable Type importer doesn't obey case restriction on post_status field

[jgbishop]

Exported data from Movable Type 3.34 uses status values like "Publish" instead of "publish." Since WordPress expects the post_status field to be lower case, the Movable Type importer needs to force lower case on the imported data.

Steps to Reproduce:

1. Export data from Movable Type 3.34 (I assume any 3.3x Movable Type build acts the same way).
2. Import data into WordPress 2.5, using the Movable Type importer.
3. Note that the given posts have no "status" set (on the "Manage Posts" page). In the database, the posts have post_status values of "Publish" instead of "publish".

I have attached a very simple patch for the Movable Type importer, which corrects this problem.

(In [7648]) Make MT post status lower case when importing. Props jgbishop. fixes #6656 for 2.5

(In [7649]) Make MT post status lower case when importing. Props jgbishop. fixes #6656 for trunk