title: Django psycopg2.OperationalError: fe_sendauth error but not connecting to postgresql database
body: <p>I am using the following sqlite connection in my myapp/settings.py file:</p>
  
  <pre><code>DATABASES = {
      'default': {
          'ENGINE': 'django.db.backends.sqlite3',
          'NAME': ':testdb:',
          #I also tried 'NAME': 'testdb',
      },
  }
  </code></pre>
  
  <p>in my manage.py file I am using:</p>
  
  <pre><code>if __name__ == "__main__":
      os.environ.setdefault("myapp.settings")
      from django.core.management import execute_from_command_line
      execute_from_command_line(sys.argv)
  </code></pre>
  
  <p>On running ./manage.py migrate on the command line I get the following error:</p>
  
  <pre><code>django.db.utils.OperationalError: fe_sendauth: no password supplied
  </code></pre>
  
  <p>I tried removing psycopg2 and re-ran the migration and get the following error:</p>
  
  <pre><code>django.core.exceptions.ImproperlyConfigured: Error loading psycopg2 module: No module named 'psycopg2'
  </code></pre>
  
  <p>I can't work out why django is trying to connect to a psql database where the only DATABSES configuration in the application is for sqlite3.</p>
  
  <p>Could this be due to a dependency?</p>