EventEmitter leak in daemon-manager

[jmatsushita]

Here's a warning stack trace when running COUCH_HOST=http://localhost:5984 TIMEOUT=120000 mocha --trace-warnings --full-trace ./tests/express-pouchdb/*:

(node:80520) Warning: Possible EventEmitter memory leak detected. 11 destroyed listeners added. Use emitter.setMaxListeners() to increase limit
    at _addListener (events.js:259:19)
    at EventEmitter.addListener (events.js:275:10)
    at start (./pouchdb-server/packages/node_modules/express-pouchdb/lib/routes/db-updates.js:18:15)
    at ./pouchdb-server/packages/node_modules/express-pouchdb/lib/daemon-manager.js:28:16
    at process._tickCallback (internal/process/next_tick.js:103:7)