test/log: check levels
test/log: check levels

Add checks on log levels:
- default values for rte_log_register and RTE_LOG_REGISTER,
- level changes with rte_log_set_level and consorts

Signed-off-by: David Marchand <f28529695cfa9e3e1eb84e7072aa626af4abb18e@redhat.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk