app/crypto-perf: fix string not null terminated
app/crypto-perf: fix string not null terminated

This commit fixes the case where the string buffer may not have
a null terminator if the source string's length is equal to the
buffer size.

Coverity issue: 141069
Fixes: f8be1786b1b8 ("app/crypto-perf: introduce performance test application")

Signed-off-by: Aleksander Gajewski <c9bcf95ca750ef9d4cf9dce950d78c04ece384df@intel.com>
Acked-by: Pablo de Lara <28355d9cfe41bb8148aea0fb24f47aae8f4217a1@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk