Load env variables before c.config()

If the env variables are loaded after the config object is created, they aren't set in the Environment object inside the config object which causes RBE to not work

Bug: b/198045383
Test: Tested by running a build against rvc-dev branch and ensuring it works.
Change-Id: I509289467df81e5535b4cbbfe4e5eb336c0e4e59