Changed python proto build to use shared protos
diff --git a/tools/run_tests/run_interop_tests.py b/tools/run_tests/run_interop_tests.py
index 28b91f8..fb2be22 100755
--- a/tools/run_tests/run_interop_tests.py
+++ b/tools/run_tests/run_interop_tests.py
@@ -314,7 +314,8 @@
     ]
 
   def global_env(self):
-    return {'LD_LIBRARY_PATH': '{}/libs/opt'.format(DOCKER_WORKDIR_ROOT)}
+    return {'LD_LIBRARY_PATH': '{}/libs/opt'.format(DOCKER_WORKDIR_ROOT),
+            'PYTHONPATH': '{}/src/python/gens'.format(DOCKER_WORKDIR_ROOT)}
 
   def unimplemented_test_cases(self):
     return _SKIP_ADVANCED + _SKIP_COMPRESSION + ['jwt_token_creds',