properly quote the extension name so it actually installs

# Description of your patch

Properly quotes extension names when installing them to prevent extensions with hyphens or other characters in them from being interpreted by PostgreSQL. For example, "uuid-ossp" was failing to install because PostgreSQL was trying to subtract ossp from uuid.

# Estimated risk

Minimal; at worst the extensions won't install.

# Components involved

PostgreSQL, Chef

# Description of testing done

Tested on two independent clusters with PostgreSQL 9.2. ey recipes upload -e <whatever> --apply. Works in both cases. See no reason it wouldn't work on a PostgreSQL solo environment either.

# QA Instructions

[9.0, 9.1, 9.2].each do
  ey recipes upload -e <your env> --apply
  Verify no errors with chef
  Verify that extensions are created through PostgreSQL console
end