Rename onyxc_int.h to av1_common_int.h.

In libvpx/vp8/common/onyxc_int.h, the purpose of the header is to define
struct VP8Common. In libvpx/vp9/common/vp9_onyxc_int.h and
av1/common/onyxc_int.h, this header file does much more than define
struct VP9Common and struct AV1Common, but I think the file name
"av1_common_int.h" still makes sense. It can be interpreted as the
internal header that defines struct AV1Common or as the internal
header in the av1/common/ directory.

Change-Id: I2ddc703b609ab2534b9e8166ed2f6db2a78371a0
diff --git a/examples/inspect.c b/examples/inspect.c
index f7422ac..526bdc1 100644
--- a/examples/inspect.c
+++ b/examples/inspect.c
@@ -29,7 +29,7 @@
 
 #include "aom/aom_decoder.h"
 #include "aom/aomdx.h"
-#include "av1/common/onyxc_int.h"
+#include "av1/common/av1_common_int.h"
 
 #if CONFIG_ACCOUNTING
 #include "av1/decoder/accounting.h"