tox: remove obsolete whitelist_externals

Author: blueyed

tox.ini

@@ -17,7 +17,6 @@ envlist =
     docs
 
 [testenv]
-whitelist_externals = env
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest --lsof -ra {posargs:testing}
     coverage: coverage combine
@@ -61,7 +60,6 @@ deps =
     nose
     hypothesis>=3.56
     {env:_PYTEST_TOX_EXTRA_DEP:}
-whitelist_externals = env
 passenv = USER USERNAME TRAVIS
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -n auto -ra {posargs:testing}
@@ -82,7 +80,6 @@ platform = linux|darwin
 deps =
     pexpect
     {env:_PYTEST_TOX_EXTRA_DEP:}
-whitelist_externals = env
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -ra test_pdb.py test_terminal.py test_unittest.py
 
@@ -103,7 +100,6 @@ changedir=testing
 setenv =
     {[testenv]setenv}
     PYTHONDONTWRITEBYTECODE=1
-whitelist_externals = env
 passenv = USER USERNAME TRAVIS
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -n auto -ra {posargs:.}
@@ -112,7 +108,6 @@ commands =
 deps =
     twisted
     {env:_PYTEST_TOX_EXTRA_DEP:}
-whitelist_externals = env
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -ra {posargs:testing/test_unittest.py}
 
@@ -124,7 +119,6 @@ commands = {[testenv:py27-trial]commands}
 deps =
     numpy
     {env:_PYTEST_TOX_EXTRA_DEP:}
-whitelist_externals = env
 commands=
   {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -ra {posargs:testing/python/approx.py}
 
@@ -160,7 +154,6 @@ skipsdist = True
 deps =
     PyYAML
     {env:_PYTEST_TOX_EXTRA_DEP:}
-whitelist_externals = env
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -ra doc/en
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest --doctest-modules --pyargs _pytest