do not hardcode the python package version

test/distrib/python/run_distrib_test.sh

@@ -32,8 +32,8 @@ set -ex
 
 cd $(dirname $0)
 
-# TODO(jtattermusch): replace the version number
-SDIST_ARCHIVE="$EXTERNAL_GIT_ROOT/input_artifacts/grpcio-0.12.0b8.tar.gz"
+# Pick up the source dist archive whatever its version is
+SDIST_ARCHIVE=$EXTERNAL_GIT_ROOT/input_artifacts/grpcio-*.tar.gz
 BDIST_DIR="file://$EXTERNAL_GIT_ROOT/input_artifacts"
 
 if [ ! -f "${SDIST_ARCHIVE}" ]