snmp_set_var_typed_value function does not epxect counter64 values as a
uint64_t, but as a struct counter64. Their binary representation differs by
order of 32bit words. By this it was wrongly seen as a endianess problem.
Since some status objects use 64bit values for calculations it is more
convenient to use uint64_t in our structures, then convert to struct counter64
just before passing data to the SNMP engine.

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