userspace/snmpd: add verbosity to the wrsOSStatusGroup

There are some side effects of this commit:
--print error/warning/warning_na for every partition that causes a problem;
  before error was reported only only for first parition causin a problem
--print warning when at least one temperature threshold is not set;
  before when all were not set
--report WRS_TEMPERATURE_WARNING_TOO_HIGH, even one of the threshold is not set

Signed-off-by: Adam Wujek <adam.wujek@cern.ch>