TF_LOG is not working

[kilimandjango]

Issue Summary:

When setting a log level, tfmake is not being executed.

Steps to reproduce:

1. Setup a Terraform project with cookiecutter or manually
2. Initialize TF project with aws-vault exec innogy-dev -- tfmake select env=dev
3. Execute TF plan with TF_LOG=DEBUG aws-vault exec innogy-dev-admin -- tfmake plan

Actual behavior:

The TF plan is not created as the env variable seems to be somewhere not correctly being parsed:

$ TF_LOG=DEBUG aws-vault exec innogy-dev-admin -- tfmake plan Enter token for arn:aws:iam::XXX:mfa/XXX@XXX.com: 394226 Error: environment '2020/05/18 10:13:50 [WARN] Log levels other than TRACE are currently unreliable, and are supported only for backward compatibility. Use TF_LOG=TRACE to see Terraform's internal logs. 2020/05/18 10:13:50 [INFO] Terraform version: 0.12.19 2020/05/18 10:13:50 [INFO] Go runtime version: go1.12.13 2020/05/18 10:13:50 [INFO] CLI args: []string{"/usr/local/bin/terraform", "workspace", "show"} 2020/05/18 10:13:50 [DEBUG] Attempting to open CLI config file: /Users/kilimandjango/.terraformrc 2020/05/18 10:13:50 [DEBUG] File doesn't exist, but doesn't need to. Ignoring. 2020/05/18 10:13:50 [INFO] CLI command args: []string{"workspace", "show"} dev' is not supported (expecting: dev, tst, acc, prd)

Expected behavior:

The Terraform plan is created.

Additional Notes:

I updated to the recent version:
$ tfmake --version tfmake, version 1.0.15

It worked before when using version 1.0.3