Excerpt mode shows post even if user is not allowed to

In excerpt view, show the excerpt only if the user can read_post.

http://core.trac.wordpress.org/changeset/21086/branches/3.3

This vulnerability affects the following application versions:

• WordPress 3.1
• WordPress 3.1.1
• WordPress 3.1.2
• WordPress 3.1.3
• WordPress 3.1.4
• WordPress 3.2
• WordPress 3.2.1
• WordPress 3.3
• WordPress 3.3.1
• WordPress 3.3.2