Fix wp admin bar keyword density check link

Issue #802
Merge branch 'master' of git://github.com/Yoast/wordpress-seo into Issue-802-admin-bar-link

Conflicts:
	readme.txt
Merge branch 'master' of git://github.com/Yoast/wordpress-seo into Issue-802-admin-bar-link

Conflicts:
	readme.txt
Merge branch 'master' of git://github.com/Yoast/wordpress-seo into Issue-802-admin-bar-link

Conflicts:
	readme.txt
Merge pull request #804 from jrfnl/Issue-802-admin-bar-link

Fix wp admin bar keyword density check link