Add missing postgress blobs from cf-services-release

Add back the following blobs:
```
postgresql/postgresql-9.1-x86_64.tar.gz 25.3M
postgresql/postgresql-9.2.4-x86_64.tar.gz       10.0M
postgresql/postgresql-initdb-9.1-x86_64.tar.gz  3.7M
postgresql/postgresql-initdb-9.2-x86_64.tar.gz  4.0M
```

From [cf-services-release](https://github.com/cloudfoundry/cf-services-release/blob/3662ddd964f66ea76f2b50dcdff6ee8420c1ac54/config/blobs.yml)