Only output statuses with error conditions, revised

[asdorsey]

By default:
If the status of the sensor being checked doesn't match a list of "OK" statuses, return 1 (WARNING) and output that status. Otherwise, return 0 (OK).

This change lets Nagios alert correctly whenever a hardware device is failing or otherwise in a non-optimal state on the host being questioned.

With -v or --verbose:
Report as the original script does - all sensor statuses are provided.

Output examples:

# ./check-idrac-sensor.py -H 192.168.1.10 -u root -p notarealpassword
OK

# ./check-idrac-sensor.py -v -H 192.168.1.10 -u root -p notarealpassword
ps2_status - PRESENT;ps1_status - PRESENT;system_board_fan_redundancy - FULLREDUNDANT;system_board_ps_redundancy - FULLREDUNDANT;system_board_power_optimized - OK;perc1_romb_battery - OK;system_board_cmos_battery - OK;perc2_romb_battery - OK;system_board_intrusion - POWERON;ps1_current_1 - OK;system_board_pwr_consumption - OK;ps2_current_2 - OK;cpu1_pll_pg - OK;system_board_bp1_5v_pg - OK;cpu2_m01_vtt_pg - OK;cpu1_m23_vtt_pg - OK;cpu1_vcore_pg - OK;system_board_ps2_pg_fail - OK;cpu2_m01_vddq_pg - OK;cpu1_m23_vddq_pg - OK;cpu1_m01_vtt_pg - OK;cpu2_m23_vddq_pg - OK;system_board_fetdrv_pg - OK;ps1_voltage_1 - OK;cpu2_m23_vtt_pg - OK;system_board_1.5v_pg - OK;cpu2_pll_pg - OK;system_board_3.3v_pg - OK;system_board_ndc_pg - OK;cpu1_vsa_pg - OK;system_board_ps1_pg_fail - OK;cpu2_vtt_pg - OK;ps2_voltage_2 - OK;cpu1_m01_vddq_pg - OK;system_board_1.1v_pg - OK;cpu2_vcore_pg - OK;cpu1_vtt_pg - OK;system_board_5v_pg - OK;cpu2_vsa_pg - OK;dimm_b12 - N/A;dimm_b11 - N/A;dimm_b10 - N/A;dimm_a6 - N/A;dimm_a7 - N/A;dimm_a4 - N/A;dimm_a5 - N/A;dimm_a2 - OK;dimm_a3 - N/A;dimm_a1 - OK;dimm_a8 - N/A;dimm_a9 - N/A;dimm_a10 - N/A;dimm_a11 - N/A;dimm_a12 - N/A;dimm_b9 - N/A;dimm_b8 - N/A;dimm_b7 - N/A;dimm_b6 - N/A;dimm_b5 - N/A;dimm_b4 - N/A;dimm_b3 - N/A;dimm_b2 - OK;dimm_b1 - OK;cpu2_status - OK;cpu1_status - OK;