Fix logic to parse JSON responses in Form wrapper (#15)

Author: ayushn21

lib/async/rest/wrapper/form.rb

@@ -34,10 +34,9 @@ def prepare_request(request, payload)
 				end
 
 				def parser_for(response)
-					if content_type = response.headers["content-type"]
-						if parser = @content_types[content_type]
-							return parser
-						end
+					media_type, _ = response.headers["content-type"].split(";")
+					if media_type && parser = @content_types[media_type]
+						return parser
 					end
 
 					return super