Clear buffer lists in stop() so we won't free the buffers again.
Bug: 5073626

Change-Id: Ia41fc089568b48de005235d66c9b5b1a5f72b5ca
diff --git a/libvideoeditor/vss/stagefrightshells/src/VideoEditorVideoEncoder.cpp b/libvideoeditor/vss/stagefrightshells/src/VideoEditorVideoEncoder.cpp
index eb74bf2..7152ccd 100755
--- a/libvideoeditor/vss/stagefrightshells/src/VideoEditorVideoEncoder.cpp
+++ b/libvideoeditor/vss/stagefrightshells/src/VideoEditorVideoEncoder.cpp
@@ -320,6 +320,9 @@
     for (size_t i = 0; i < mReleaseBuffers.size(); i++) {
         mReleaseBuffers.itemAt(i)->release();
     }
+
+    mBuffers.clear();
+    mReleaseBuffers.clear();
 }
 
 MediaBuffer* VideoEditorVideoEncoderPuller::getBufferNonBlocking() {