Cause replica to error when pip install fails

(cherry picked from commit 394862b)

Author: deliahu

pkg/workloads/cortex/serve/run.sh

@@ -14,6 +14,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+set -e
+
 export PYTHONPATH=$PYTHONPATH:$PYTHON_PATH
 
 if [ -f "/mnt/project/requirements.txt" ]; then