#1357 add support for double byte characters

[Josef Ridky]

Net-SNMP isn't able to handle double byte characters like UTF-8.
Though it can handle single byte characters (US-ASCII characters) properly, UTF-8 and ShiftJIS characters are displays as "........."

Steps to Reproduce:
- Edit /etc/snmp/snmptrapd.conf and add or uncomment the following line.

authCommunity log,execute,net public

• Strat snmptrapd service.

# systemctl start snmptrapd

• Run the following command.

# snmptrap -v 2c -c public localhost  ''  .1.3.6.1.4.1.8072.2.1.3 .1.3.6.1.4.1.8072.2.1.3 s "データ"

• Check the /var/log/messages or journalctl

Attached patch bring support for double byte characters (UTF-8). Please, review this patch and consider to add it to Net-SNMP.

All comments are welcome.