theme_admin_block_display colspan adjustment

Hi,

First patch here, so I hope I did it right.

In the theme_admin_block_display function, the colspan defaults to 7 columns for sites with throttle enabled, and 6 for sites without throttle, when really there are only 6 columns with throttle and 5 without. The attached patch just changes the defaults to 6 and 5.

With Throttle

1. Block
2. Region
3. Weight
4. Throttle
5. Operations (configure)
6. Operations (delete)

Without Throttle

1. Block
2. Region
3. Weight
4. Operations (configure)
5. Operations (delete)