Clang and GCC's warning option of `-Wbraced-scalar-init` warns
at seeing superfluous use of braces, like:
```
/home/kefu/dev/scylladb/test/raft/randomized_nemesis_test.cc:2187:32: error: braces around scalar initializer [-Werror,-Wbraced-scalar-init]
.snapshot_threshold{1},
^~~
```
usually, this does not hurt. but by taking the braces out, we have
a more readable piece of code, and less warnings.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#15086
8cc215db96