Change reliable_get_buf_sequenced to reliable_get_entry_sequenced

Change reliable_get_buf_sequenced to reliable_get_entry_sequenced

This returns not just the buffer of a reliable_entry but the whole
entry. This allows the caller to also inspect the original opcode
and packet id.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Frank Lichtenheld <frank@lichtenheld.com>
Message-Id: <20220422142953.3805364-11-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg24153.html

Signed-off-by: Gert Doering <gert@greenie.muc.de>