Instead of constantly calling the mibII_idle function when the server is not busy
call the function only once every 10 seconds to avoid bsnmpd constantly doing
gettimeofday syscalls. Make the idle polling interval confugurable via
begemotIfDataPoll.
Reported and tested by: misho (at) aitbg (dot) com
Oked by: harti
MFC after: 1 week