dbt sometimes writes a .user.yml and ignores configs

[beckjake]

Issue

If you pass dbt a relative path to --profiles-dir or the DBT_PROFILES_DIR environment variable and execute from a subdirectory, dbt will look for the user cookie and profiles.yml in different places (the latter correct, the former incorrect).

Results

What happened? What did you expect to happen?
I got a ./profiles/.user.yml and my settings were ignored. I expected my settings to be respected or to receive an error, and to not have a new file.

Suggested fixes:
My preference: don't allow users to run dbt from subdirectories.
Other option: defer loading of the user config until after we've found dbt_project.yml.

System information

The output of dbt --version:

0.14.0

The operating system you're running on:
Any

The python version you're using (probably the output of python --version)
Any

Steps to reproduce

In as much detail as possible, please provide steps to reproduce the issue. Sample data that triggers the issue, example models, etc are all very helpful here.

1. Make a dbt project in ${project_root}
2. put your profiles.yml in ${project_root}/profiles
3. Make a subdirectory (${project_root}/models) and cd into it
4. Run dbt with the relative path to the profiles directory as an argument to --profiles-dir: dbt run --profiles-dir profiles
5. You will now have a ${project_root}/models/profiles/.user.yml with cookie information. Also, any settings in your profiles.yml won't be respected.

[drewbanin]

Let's definitely preserve the behavior where you can execute dbt from subdirs of the project. Let's instead pursue this approach:

defer loading of the user config until after we've found dbt_project.yml