Use py.test from run_tests.py

Also updates the version of grpcio_test. Now that grpcio and its tests
are in different project packages, the version numbers should be kept in
sync.
diff --git a/src/python/grpcio_test/setup.py b/src/python/grpcio_test/setup.py
index 7987103..925c327 100644
--- a/src/python/grpcio_test/setup.py
+++ b/src/python/grpcio_test/setup.py
@@ -52,21 +52,28 @@
         'credentials/server1.pem',]
 }
 
-_INSTALL_REQUIRES = ['oauth2client>=1.4.7', 'grpcio>=0.10.0a0']
+_SETUP_REQUIRES = (
+    'pytest>=2.6',
+    'pytest-cov>=2.0',
+    'pytest-xdist>=1.11',
+)
+
+_INSTALL_REQUIRES = (
+    'oauth2client>=1.4.7',
+    'grpcio>=0.10.0a0',
+)
+
+_COMMAND_CLASS = {
+    'test': commands.RunTests
+}
 
 setuptools.setup(
     name='grpcio_test',
-    version='0.0.1',
+    version='0.10.0a0',
     packages=_PACKAGES,
     package_dir=_PACKAGE_DIRECTORIES,
     package_data=_PACKAGE_DATA,
-    install_requires=_INSTALL_REQUIRES,
-    setup_requires=(
-        'pytest>=2.6',
-        'pytest-cov>=2.0',
-        'pytest-xdist>=1.11',
-    ),
-    cmdclass={
-        'test': commands.RunTests
-    }
+    install_requires=_INSTALL_REQUIRES + _SETUP_REQUIRES,
+    setup_requires=_SETUP_REQUIRES,
+    cmdclass=_COMMAND_CLASS
 )