mon command: fix calling free() code style-mix

mon command: fix calling free() code style-mix

the error case checked for nullness on outbuf but not outs, while the
normal code path did the exact reverse, which is rather confusing for
any reader, as they could think there's something implied by this.

There isn't and rados' rados_buffer_free is already having its own
non-null check, not that it would matter much to call free with null
anyway.., but always using the rados provided method ensures tracing
shows the free, which could be good on debugging..

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>