Upgrade CF RDS instance to t2.small
Upgrade CF RDS instance to t2.small

As part of the work to migrate Diego to use SQL, it was noted that the
performance of the platform is limited by the small size of this
instance. To quote from the story[1]:

> The main limiting factor seems to the memory available for current
> t2.micro instance which reduces the number of connections that can be
> established with DB.

Upgrading to a t2.small gives double the available RAM (2Gig).

[1]https://www.pivotaltracker.com/story/show/136100681

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