Fix bad function call in thermos_task_runner.

Bugs closed: AURORA-836

Reviewed at https://reviews.apache.org/r/26711/
Disable requests http connection logging.

Bugs closed: AURORA-770

Reviewed at https://reviews.apache.org/r/26424/
Limit the amount of work done while bootstrapping thrift.

Reviewed at https://reviews.apache.org/r/26720/
Use JobKey when getting roles to authenticate against.

Testing Done:
./gradlew clean test

Bugs closed: AURORA-837

Reviewed at https://reviews.apache.org/r/26716/
Use python2.7 for thrift_wrapper_codegen.

Reviewed at https://reviews.apache.org/r/26764/
Simplify the ResourceSlot class.
Hacky Wiring.
WIP.
Add TODOs.