Update modules and remove unused travis settings

[kazuhitoyokoi]

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Proposed changes

I updated node-red-node-test-helper module and removed the unused travis settings.

Checklist

• I have read the contribution guidelines
• For non-bugfix PRs, I have discussed this change on the mailing list/slack team.
• I have run grunt to verify the unit tests pass
• I have added suitable unit tests to cover the new/changed functionality

[coveralls]

Coverage remained the same at 76.898% when pulling f5043ed on kazuhitoyokoi:master into f9f522c on node-red:master.

[kazuhitoyokoi]

@HiroyasuNishiyama Thank you.