dbt deps fails for non english shells

[vijaykiran]

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Issue

Running dbt deps fails on machines with Locale set to any language other than English

Issue description

The command was (to check Spanish Locale) LC_ALL=es_ES dbt deps in a project with packages.yml referring to dbt-utils

Results

Runs fine with en_US, but failed for Spanish.

System information

The output of dbt --version:

₹ dbt --version
installed version: 0.12.1
   latest version: 0.12.1

Up to date!

The operating system you're running on: Mac OS Mojave

The python version you're using (probably the output of python --version): Python 3.6.5

Steps to reproduce

Any dbt projects with a one dependency in projects.yml. Here is the output:

analytics-core git:(master) 1M 2A ₹ LC_ALL=es_ES dbt deps
Encountered an error:
'NoneType' object has no attribute 'group'
Traceback (most recent call last):
  File "/Users/vijay/.pyenv/versions/3.6.5/lib/python3.6/site-packages/dbt/main.py", line 76, in main
    results, succeeded = handle_and_check(args)
  File "/Users/vijay/.pyenv/versions/3.6.5/lib/python3.6/site-packages/dbt/main.py", line 126, in handle_and_check
    task, res = run_from_args(parsed)
  File "/Users/vijay/.pyenv/versions/3.6.5/lib/python3.6/site-packages/dbt/main.py", line 181, in run_from_args
    results = run_from_task(task, cfg, parsed)
  File "/Users/vijay/.pyenv/versions/3.6.5/lib/python3.6/site-packages/dbt/main.py", line 189, in run_from_task
    result = task.run()
  File "/Users/vijay/.pyenv/versions/3.6.5/lib/python3.6/site-packages/dbt/task/deps.py", line 439, in run
    target_config = final_deps[name].fetch_metadata(self.config)
  File "/Users/vijay/.pyenv/versions/3.6.5/lib/python3.6/site-packages/dbt/task/deps.py", line 83, in fetch_metadata
    self._cached_metadata = self._fetch_metadata(project)
  File "/Users/vijay/.pyenv/versions/3.6.5/lib/python3.6/site-packages/dbt/task/deps.py", line 239, in _fetch_metadata
    path = self._checkout(project)
  File "/Users/vijay/.pyenv/versions/3.6.5/lib/python3.6/site-packages/dbt/task/deps.py", line 235, in _checkout
    dirname=self._checkout_name)
  File "/Users/vijay/.pyenv/versions/3.6.5/lib/python3.6/site-packages/dbt/clients/git.py", line 77, in clone_and_checkout
    directory = matches.group(1)
AttributeError: 'NoneType' object has no attribute 'group'

[vijaykiran]

Looks like this is occurring because the code is relying on git command out and err to be in English https://github.com/fishtown-analytics/dbt/blob/dev/stephen-girard/core/dbt/clients/git.py#L75