Post-push fix for warnings with clang on Mac:

storage/temptable/src/test.cc:414:45: error:
suggest braces around initialization of
      subobject [-Werror,-Wmissing-braces]
  std::array<const unsigned char *, 2> rows{row1, row2};

Change-Id: Ia41860b9360ab5a05986e88dd01caece027666e8