Merge pull request mongodb#1505 from mongodb/greenkeeper-readable-stream-2.2.7

Update readable-stream to version 2.2.7 🚀

Author: christkv

package.json

@@ -16,7 +16,7 @@
  "es6-promise": "3.2.1",
  "mongodb-core": "2.1.9",
  "mongodb-core": "christkv/mongodb-core#2.0",
- "readable-stream": "2.1.5"
+ "readable-stream": "2.2.7"
  },
  "devDependencies": {
  "JSONStream": "^1.0.7",