Add RDS access to the rustc-perf-two collector

[Kobzol]

I'll need the RDS change to get deployed.

[marcoieni]

PLAY RECAP *************************************************************************************************************************************************************
rustc-perf-one.infra.rust-lang.org : ok=136  changed=9    unreachable=0    failed=0    skipped=91   rescued=0    ignored=2
rustc-perf-two.infra.rust-lang.org : ok=136  changed=10   unreachable=0    failed=0    skipped=91   rescued=0    ignored=2

[marcoieni]

I also applied terraform.

Apply complete! Resources: 0 added, 1 changed, 0 destroyed.