Delete commented out code

Author: owen-mc

go/ql/lib/semmle/go/frameworks/Email.qll

@@ -103,18 +103,3 @@ private class MultipartNewWriterModel extends TaintTracking::FunctionModel {
     input.isResult() and output.isParameter(0)
   }
 }
-// /**
-//  * A taint model of the `Data` method of `Client` from `net/smtp`.
-//  *
-//  * If tainted data is written to the writer created by this method, the client
-//  * should be considered tainted as well.
-//  */
-// private class SmtpClientDataModel extends TaintTracking::FunctionModel, Method {
-//   SmtpClientDataModel() {
-//     // func (c *Client) Data() (io.WriteCloser, error)
-//     this.hasQualifiedName("net/smtp", "Client", "Data")
-//   }
-//   override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
-//     input.isResult(0) and output.isReceiver()
-//   }
-// }