Fix pip._internal import in tests

Missed fixing the import of 'get_installed_distributions' in tests in
the earlier commit.

Also fixed indentation

pipdeptree.py

@@ -565,7 +565,7 @@ def _get_args():
 def main():
  args = _get_args()
  pkgs = get_installed_distributions(local_only=args.local_only,
-  user_only=args.user_only)
+ user_only=args.user_only)
 
  dist_index = build_dist_index(pkgs)
  tree = construct_tree(dist_index)

tests/virtualenvs/pickle_env.py

@@ -7,15 +7,15 @@
 import sys
 
 try:
- import pip._internal as pip
+ from pip._internal.utils.misc import get_installed_distributions
 except ImportError:
- import pip
+ from pip import get_installed_distributions
 
 
 def main():
  default_skip = ['setuptools', 'pip', 'python', 'distribute']
  skip = default_skip + ['pipdeptree']
- pkgs = pip.get_installed_distributions(local_only=True, skip=skip)
+ pkgs = get_installed_distributions(local_only=True, skip=skip)
  pickle.dump(pkgs, sys.stdout)
  return 0