Fix "EADDRINUSE" error

[bggbr]

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

Proposed changes

It is necessary to partially modify the EADDRINUSE error handling code that occurs when ports are duplicated.

In node-red/red.js file, the if conditional statement that occurs when ports are duplicated is incorrect. The EADDRINUSE error is the "code" property of the err object, but is currently conditional on the "errno" property.

So EADDRINUSE errors are caught in Uncaught Exception.

Checklist

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

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: bggbr (892d21f)

[knolleary]

Well spotted. Thanks for the fix.

[coveralls]

Coverage: 68.554%. Remained the same when pulling 892d21f on bggbr:master into adfc5b3 on node-red:master.