apps/storeutl.c: avoid signed integer overflow in indent_printf()

apps/storeutl.c: avoid signed integer overflow in indent_printf()

As two arbitrarily large printf return values can trigger signed integer
overflow, rewrite the return value handling to avoid it.

Fixes: fb43ddceda79 "Add a recursive option to 'openssl storeutl'"
Resolves: https://scan5.scan.coverity.com/#/project-view/65248/10222?selectedIssue=1665428
References: https://github.com/openssl/project/issues/1432
Signed-off-by: Eugene Syromiatnikov <esyr@openssl.org>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/28648)