Fix software avc encoder crash at EOS.

Change-Id: I738dc24556e41ce518b67babeff16cd934c2d1b1
diff --git a/media/libstagefright/codecs/avc/enc/AVCEncoder.cpp b/media/libstagefright/codecs/avc/enc/AVCEncoder.cpp
index 0d89e02..a99186b 100644
--- a/media/libstagefright/codecs/avc/enc/AVCEncoder.cpp
+++ b/media/libstagefright/codecs/avc/enc/AVCEncoder.cpp
@@ -391,8 +391,6 @@
         if (err != OK) {
             LOGE("Failed to read input video frame: %d", err);
             outputBuffer->release();
-            mInputBuffer->release();
-            mInputBuffer = NULL;
             return err;
         }