Change default on Python install option

src/python/grpcio/commands.py

@@ -135,7 +135,7 @@ class Install(install.install, EggNameMixin):
 
   def initialize_options(self):
     install.install.initialize_options(self)
-    self.use_grpc_custom_bdist = False
+    self.use_grpc_custom_bdist = bool(int(os.environ.get('GRPC_PYTHON_USE_CUSTOM_BDIST', '1')))
 
   def finalize_options(self):
     install.install.finalize_options(self)

test/distrib/python/run_distrib_test.sh

@@ -52,7 +52,6 @@ pip install --upgrade futures
 
 GRPC_PYTHON_BINARIES_REPOSITORY="${BDIST_DIR}" \
     pip install \
-    "${SDIST_ARCHIVE}" \
-    --install-option="--use-grpc-custom-bdist"
+    "${SDIST_ARCHIVE}"
 
 python distribtest.py

tools/run_tests/build_artifact_python.sh

@@ -39,11 +39,13 @@ then
   pip install -rrequirements.txt
 fi
 
-GRPC_PYTHON_BUILD_WITH_CYTHON=1 ${SETARCH_CMD} python setup.py \
-    bdist_wheel \
-    sdist \
+GRPC_PYTHON_USE_CUSTOM_BDIST=0  \
+GRPC_PYTHON_BUILD_WITH_CYTHON=1 \
+${SETARCH_CMD} python setup.py  \
+    bdist_wheel                 \
+    sdist                       \
     bdist_egg_grpc_custom
 
 mkdir -p artifacts
 
-cp -r dist/* artifacts
+cp -r dist/* artifacts