Bug 1701864 - Prevent an error when using nsMsgSend.cpp together with SmtpService.jsm. r=mkmelin

The problem is SmtpService.jsm doesn't use nsISmtpUrl, so do_QueryInterface would always fail.

--HG--
extra : rebase_source : 9be167f7f3557f1a2ecbe90807daab3e9855a014

mailnews/compose/src/nsMsgSend.cpp

@@ -2867,8 +2867,9 @@ nsresult nsMsgComposeAndSend::DeliverFileAsMail() {
         ""_ns, getter_AddRefs(runningUrl), getter_AddRefs(mRunningRequest));
     // set envid on the returned URL
     if (NS_SUCCEEDED(rv)) {
-      nsCOMPtr<nsISmtpUrl> smtpUrl(do_QueryInterface(runningUrl, &rv));
-      if (NS_SUCCEEDED(rv))
+      nsresult rv2;
+      nsCOMPtr<nsISmtpUrl> smtpUrl(do_QueryInterface(runningUrl, &rv2));
+      if (NS_SUCCEEDED(rv2))
         smtpUrl->SetDsnEnvid(nsDependentCString(mCompFields->GetMessageId()));
     }
   }