Fix Travis error

[kazuhitoyokoi]

Types of changes

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

Proposed changes

Current test case for swagger node fails because there isn't the key, "123" in the data from swagger petstore server.
I changed "123" to "available" which the server returns as default key.

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 32.893% when pulling 0b4c2d0 on kazuhitoyokoi:master into 0f9728a on node-red:master.