metatag 7.x-1.0-beta9

The main reason behind this release is to solve two bugs some sites run into updating to 1.0-beta8 if they had used an earlier dev release.

Full changelog:

• #2174363 by DamienMcKenna: Changed update 7018 to avoid attempting to create duplicate records when updating; instead should there be a collision the record with revision_id 0 will be deleted.
• #2176351 by DamienMcKenna: 403 and 404 error pages will use the global default for the page title instead of copying the homepage's.
• #2175843 by DamienMcKenna: It was possible to get to update 7016 without the revision_id field existing, so make sure it exists.
• #2081787 by attila.fekete: Don't let Metatag:Views overwrite the frontpage meta tag config, matching how Metatag:Panels works.
• #2176375 by DamienMcKenna: Added note to README.txt about the Textimage module's compatibility with Metatag.
• #2170771 by DamienMcKenna: Added support for the og:image:secure_url meta tag.