go-flutter: Blackscreen after #308

@pchampio After #308 my app only shows a blackscreen and spits out this error on linux (also tested windows with wine and got the same error):

2019/12/26 12:59:30 error.go:171: PlatformError: GLX: Failed to make context current

When running using hover run -b '@2d582358f34c257933c47e1f0591fc38c713c78c' (the previous commit) the app starts like normal so it’s definitely an issue with #308.