Fix python path typo in the start dev server script (#253)

* Fix python path typo in the start dev server script
Kill webpack in case of python error.

* Switch to use trap

* capture more signal.

scripts/setup_dev_env.sh

@@ -21,4 +21,4 @@ cd build
 cmake ..
 make -j $processors
 
-export PYTHON_PATH=$PYTHON_PATH:"$SCRIPT_DIR/.."
+export PYTHONPATH=$PYTHONPATH:"$SCRIPT_DIR/.."

scripts/start_dev_server.sh

@@ -6,9 +6,19 @@ CURRENT_DIR=`pwd`
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
 cd $SCRIPT_DIR/../frontend
+export PYTHONPATH=$PYTHONPATH:"$SCRIPT_DIR/.."
+
 ./node_modules/.bin/webpack --watch --config tool/webpack.dev.config.js --output-path=../visualdl/server/dist &
+# Track webpack pid
+WEBPACKPID=$!
+
+function finish {
+    kill -9 $WEBPACKPID
+}
 
-export PYTHON_PATH=$PYTHON_PATH:"$SCRIPT_DIR/.."
+trap finish EXIT HUP INT QUIT PIPE TERM
 
 cd $CURRENT_DIR
+
+#Run the visualDL with local PATH
 python ${SCRIPT_DIR}/../visualdl/server/visualDL "$@"