Doesn't respect request_body type

[jacobmovingfwd]

ruby-http-client/lib/ruby_http_client.rb

Line 152 in 74b7bff

@request.body = @request_body.to_json

If the request_body is already a JSON String, this over-encodes it, instead of leaving it alone. This line should check and see if it's a Hash, and format it only if needed.