Fix memory leaks

Bug: 64424279
Change-Id: I814f81d8e050132be7779310d3f1ab6b19f2e593
(cherry picked from commit 12586d1c216c52efbfd2265d240147b1c31fe543)
diff --git a/media/libstagefright/MPEG4Extractor.cpp b/media/libstagefright/MPEG4Extractor.cpp
index 1a1563a..9c096e6 100644
--- a/media/libstagefright/MPEG4Extractor.cpp
+++ b/media/libstagefright/MPEG4Extractor.cpp
@@ -4624,6 +4624,8 @@
         }
         if (size > mBuffer->size()) {
             ALOGE("buffer too small: %zu > %zu", size, mBuffer->size());
+            mBuffer->release();
+            mBuffer = NULL;
             return ERROR_BUFFER_TOO_SMALL;
         }
     }
@@ -4916,6 +4918,8 @@
         }
         if (size > mBuffer->size()) {
             ALOGE("buffer too small: %zu > %zu", size, mBuffer->size());
+            mBuffer->release();
+            mBuffer = NULL;
             return ERROR_BUFFER_TOO_SMALL;
         }
     }