patchfast-import: use mem_pool_calloc()

>
> Use mem_pool_calloc() to get a zeroed buffer instead of zeroing it
> ourselves.  This makes the code clearer and less repetitive.
>
> Signed-off-by: René Scharfe <l.s.r@web.de>
> ---
>  builtin/fast-import.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/builtin/fast-import.c b/builtin/fast-import.c
> index 444f41cf8c..92eda20683 100644
> --- a/builtin/fast-import.c
> +++ b/builtin/fast-import.c
> @@ -2809,8 +2809,7 @@ static void parse_new_tag(const char *arg)
>         enum object_type type;
>         const char *v;
>
> -       t = mem_pool_alloc(&fi_mem_pool, sizeof(struct tag));
> -       memset(t, 0, sizeof(struct tag));
> +       t = mem_pool_calloc(&fi_mem_pool, 1, sizeof(struct tag));
>         t->name = mem_pool_strdup(&fi_mem_pool, arg);
>         if (last_tag)
>                 last_tag->next_tag = t;
> --
> 2.43.0