Exclude test in find_packages (googleapis#720)

To avoid conflicts with projects that have tests in their top-level
directory:

* exlude tests in find_packages
* add include in MANIFEST.in

Closes: googleapis#688

Signed-off-by: Spyros Trigazis <[email protected]>

Author: strigazi

MANIFEST.in

@@ -1,3 +1,2 @@
-include README.md
-include LICENSE
-recursive-exclude tests *
+include README.md LICENSE CHANGELOG.md
+recursive-include tests *

setup.py

@@ -61,7 +61,7 @@
     author_email='[email protected]',
     url='http://github.com/google/oauth2client/',
     install_requires=install_requires,
-    packages=find_packages(),
+    packages=find_packages(exclude=('tests*',)),
     license='Apache 2.0',
     keywords='google oauth 2.0 http client',
     classifiers=[