Error in preferences page path-selector when there is no default value

[hicom150]

What version of this package are you using?
Latest master commit afd3b84

What operating system, Node.js, and npm version?
OSX Yosemite (10.10.5), Node.js v8.16.0, npm 6.10.2

What happened?
In preferences page when you try to push CHANGE button in Folder to watch or you try to push CHANGE button in External player an error message is throw in debug console and dialog does not open

Error: Could not call remote method 'showOpenDialog'. Check that the method signature is correct. Underlying error: Default path must be a string

What did you expect to happen?
I expect the dialog to open

Are you willing to submit a pull request to fix this bug?
Sure! 😎

[hicom150]

Should be fixed in #1653 😉

[feross]

Fixed by #1498