free src_a in unittest to fix leak

TBR=harryjin@google.com
BUG=libyuv:524

Review URL: https://codereview.chromium.org/1452083002 .

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1538
+Version: 1539
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1538
+#define LIBYUV_VERSION 1539
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

unit_test/convert_test.cc

@@ -1845,6 +1845,7 @@ TEST_F(LibYUVConvertTest, FMT_PLANAR##To##FMT_B##_##FMT_C##N) {                \
   free_aligned_buffer_64(src_y);                                               \
   free_aligned_buffer_64(src_u);                                               \
   free_aligned_buffer_64(src_v);                                               \
+  free_aligned_buffer_64(src_a);                                               \
   free_aligned_buffer_64(dst_argb_b);                                          \
   free_aligned_buffer_64(dst_argb_c);                                          \
   free_aligned_buffer_64(dst_argb_bc);                                         \