libsync: Fix a double-free.

sync_file_info, the only caller of legacy_fence_info_to_sync_file_info,
unconditionally frees legacy_info after
legacy_fence_info_to_sync_file_info is called. So, if this calloc
fails, we'll end up freeing legacy_info twice.

Bug: 27101951
Test: mma. Static analyzer complaint about double-free is gone.
Change-Id: I43bf820af9aadf30cb8eabce57416f69a8fccf89

libsync/sync.c

@@ -275,7 +275,6 @@ static struct sync_file_info* legacy_fence_info_to_sync_file_info(
     info = calloc(1, sizeof(struct sync_file_info) +
                      num_fences * sizeof(struct sync_fence_info));
     if (!info) {
-        free(legacy_info);
         return NULL;
     }
     info->sync_fence_info = (__u64)(uintptr_t)(info + 1);