apps/ciphers: Fix wrong return value when using -convert parameter

apps/ciphers: Fix wrong return value when using -convert parameter

Command 'openssl ciphers -convert <name>' always returns failure,
this patch set the correct return value.

Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Reviewed-by: Paul Yang <kaishen.yy@antfin.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/16383)

(cherry picked from commit 8b4e9c5265ffd3457ad37133502a9d8a4e8daccd)