Correct optionsf.path in modem.js

Corrects optionsf.path in modem.js for http docker hosts. The path incorrect here was not breaking anything in node; however is does break browserify. This is also a bug with browserify since it's http request is not mirroring node's behavior, but it is probably good to have the path be accurate anyways.

Before the fix `optionsf.path` was the full href: "http://localhost:4243/<path>" instead of just being "/<path>"