mythtranscode: update new length for cut-to-end

Include frames cut from the end in the New Length reported by
mythtranscode.  Fixes #9528

Author: sphery

mythtv/programs/mythtranscode/transcode.cpp

@@ -441,7 +441,10 @@ int Transcode::TranscodeFile(
             long long lastFrame = (long long)m_proginfo->
                                              GetLastFrameInPosMap() + 60;
             if (lastFrame > lastStart)
+            {
+                new_frame_count -= (lastFrame - lastStart);
                 cutStr += QString("%1").arg(lastFrame);
+            }
         }
         VERBOSE(VB_GENERAL, QString("Cutlist        : %1").arg(cutStr));
         VERBOSE(VB_GENERAL, QString("Original Length: %1 frames")