dev-python/django-configurations: Add this Raven test dependency

dev-python/django-configurations: Add this Raven test dependency

The django-cache-url dependency avoids the following test failure:

  Traceback (most recent call last):
    File "/.../configurations/utils.py", line 32, in import_by_path
      module = import_module(module_path)
    File "/usr/lib64/python3.3/importlib/__init__.py", line 90, in import_module
      return _bootstrap._gcd_import(name[level:], package, level)
    File "<frozen importlib._bootstrap>", line 1584, in _gcd_import
    File "<frozen importlib._bootstrap>", line 1565, in _find_and_load
    File "<frozen importlib._bootstrap>", line 1529, in _find_and_load_unlocked
  ImportError: No module named 'django_cache_url'

The dj-database-url dependency avoids the following test failure:

  Traceback (most recent call last):
    File "/.../configurations/utils.py", line 32, in import_by_path
      module = import_module(module_path)
    File "/usr/lib64/python3.3/importlib/__init__.py", line 90, in import_module
      return _bootstrap._gcd_import(name[level:], package, level)
    File "<frozen importlib._bootstrap>", line 1584, in _gcd_import
    File "<frozen importlib._bootstrap>", line 1565, in _find_and_load
    File "<frozen importlib._bootstrap>", line 1529, in _find_and_load_unlocked
  ImportError: No module named 'dj_database_url'

The dj-email-url dependency avoids the following test failure:

  Traceback (most recent call last):
    File "/.../configurations/utils.py", line 32, in import_by_path
      module = import_module(module_path)
    File "/usr/lib64/python3.3/importlib/__init__.py", line 90, in import_module
      return _bootstrap._gcd_import(name[level:], package, level)
    File "<frozen importlib._bootstrap>", line 1584, in _gcd_import
    File "<frozen importlib._bootstrap>", line 1565, in _find_and_load
    File "<frozen importlib._bootstrap>", line 1529, in _find_and_load_unlocked
  ImportError: No module named 'dj_email_url'

The dj-search-url dependency avoids the following test failure:

  Traceback (most recent call last):
    File "/.../configurations/utils.py", line 32, in import_by_path
      module = import_module(module_path)
    File "/usr/lib64/python3.3/importlib/__init__.py", line 90, in import_module
      return _bootstrap._gcd_import(name[level:], package, level)
    File "<frozen importlib._bootstrap>", line 1584, in _gcd_import
    File "<frozen importlib._bootstrap>", line 1565, in _find_and_load
    File "<frozen importlib._bootstrap>", line 1529, in _find_and_load_unlocked
  ImportError: No module named 'dj_search_url'