* include/functions_reporting.php: Handle empty and zero values in
get_agent_module_sla.
* include/config_process.php: SLA Period shouldn't be 0 (which is
apparently default in the database). If SLA is empty (NULL, 0, false
or '') then it get's reset to a default value.
* godmode/setup/setup.php: SLA Period was hidden because of a miscount
git-svn-id: https://svn.code.sf.net/p/pandora/code/trunk@1133 c3f86ba8-e40f-0410-aaad-9ba5e7f4b01f