Zabbix

........S. [ZBXNEXT-4002] fixed minor bugs

Fixed the use of an uninitialized variable by adding
back it's assignement. Also fixed a check for
ZBX_DB_OK instead of SUCCEED.

Fixed some complaints of ignored return values.
Just cast those to void.

Spotted by coverity

[svn merge ^/branches/dev/ZBXNEXT-4002]