OpenAPI v2 Converter: NPE when 'enum' field is available and 'type' field is missing in query parameter

[ymohdriz]

With an OAI spec as below:
swagger.txt

Got the below null pointer exception
java.lang.NullPointerException
at io.swagger.v3.parser.converter.SwaggerConverter.convert(SwaggerConverter.java:1013)
at io.swagger.v3.parser.converter.SwaggerConverter.convert(SwaggerConverter.java:535)
at io.swagger.v3.parser.converter.SwaggerConverter.convert(SwaggerConverter.java:488)
at io.swagger.v3.parser.converter.SwaggerConverter.convert(SwaggerConverter.java:203)
at io.swagger.v3.parser.converter.SwaggerConverter.readLocation(SwaggerConverter.java:93)
at io.swagger.parser.OpenAPIParser.readLocation(OpenAPIParser.java:19)
at io.swagger.parser.OpenAPIParserTest.testSimple(OpenAPIParserTest.java:51)

Thanks,
Mohammed