[deploy.sh] node-gyp rebuild

From nodejs/node-gyp README:
- `rebuild`  Runs `clean`, `configure` and `build` all in a row
- `clean`    Removes the `build` directory if it exists

This ensures `npm run deploy` succeeds if it is run a second time.
`npm run deploy` needs to be re-run if the deploy options change.

deploy.sh

@@ -86,12 +86,7 @@ fi
 make -j 8
 
 cd ../gzbridge
-if [ -d "./build" ]; then
-  # node-gym configure will fail if build already exists
-  rm -rf ./build
-fi
-$DIR/node_modules/.bin/node-gyp configure
-$DIR/node_modules/.bin/node-gyp build -d
+$DIR/node_modules/.bin/node-gyp rebuild -d
 
 RETVAL=$?
 if [ $RETVAL -ne 0 ]; then