The bug is due to the jugglingdb version used in the npm deposit of jugglingdb-mysql, so the only way to fix it is to delete the directory and copy the one you use in your main project :
cd $YOUR_PROJECT_ROOT
rm -rf node_modules/jugglingdb-mysql/node_modules/jugglingdb
cp -R node_modules/jugglingdb node_modules/jugglingdb-mysql/node_modules
I haven't tries to install the adapter manually from github, maybe it works too.
The problem is reported here https://github.com/jugglingdb/mysql-adapter/issues/46