Ensure when ParamType equals "body" name also equals "body"

Fixes the behaviour described by @jchannon in #26. When ParamType equals "body" name also equals "body".
See https://github.com/wordnik/swagger-spec/blob/master/versions/1.2.md#524-parameter-object

This commit overrules any name given in the metadata by "body" when ParamType equals "body"