Validation:"swagger" field must validate against schema

[itgirlalice]

When missing "swagger" field, the validation passed. But the "swagger" field is required in schema， so it should validate against schema.

BTY, there are three required filed "swagger", "info" and "paths", but the validation result is different.

1. Missing "swagger" field, validation pass.
2. Missing "info", validation failure failed, get error message ".info in body is required".
3. Missing "paths", get "nil pointer dereference" error, the related issue Nil pointer dereference exception while validate an swagger without path #52.

So hope the 1 and 3 could be fixed.

[itgirlalice]

@casualjim
Hi casualjim, do we have any plan on this issue?

Thanks,
Alice

[casualjim]

Yes I'll try to fix some this weekend.
The swagger version fix is relatively easy, haven't really looked into the other one yet

This is the cause for the first one: https://github.com/go-swagger/go-swagger/blob/master/spec/spec.go#L124-L126