update setup (Azure#6056)

Author: xiangyan99

sdk/core/azure-core/setup.py

@@ -42,14 +42,13 @@
     license='MIT License',
     author='Microsoft Corporation',
     author_email='[email protected]',
-    url='https://github.com/Azure/azure-sdk-for-python',
+    url='https://github.com/Azure/azure-sdk-for-python/tree/master/sdk/core/azure-core',
     classifiers=[
         'Development Status :: 4 - Beta',
         'Programming Language :: Python',
         'Programming Language :: Python :: 2',
         'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',