Drop vendoring from packaging

.coveragerc

@@ -4,4 +4,3 @@ omit =
     *standalonetemplate.py
     # oldinterpret could be removed, as it is no longer used in py26+
     *oldinterpret.py
-    vendored_packages

setup.py

@@ -75,7 +75,7 @@ def main():
         setup_requires=['setuptools-scm'],
         install_requires=install_requires,
         extras_require=extras_require,
-        packages=['_pytest', '_pytest.assertion', '_pytest._code', '_pytest.vendored_packages'],
+        packages=['_pytest', '_pytest.assertion', '_pytest._code'],
         py_modules=['pytest'],
         zip_safe=False,
     )

tox.ini

@@ -162,7 +162,7 @@ usedevelop = True
 deps =
     autopep8
 commands =
-    autopep8 --in-place -r --max-line-length=120 --exclude=vendored_packages,test_source_multiline_block.py _pytest testing
+    autopep8 --in-place -r --max-line-length=120 --exclude=test_source_multiline_block.py _pytest testing
 
 [testenv:jython]
 changedir = testing
@@ -213,4 +213,3 @@ filterwarnings =
 
 [flake8]
 max-line-length = 120
-exclude = _pytest/vendored_packages/pluggy.py