Fixed parsing of channel information

The fix assumes channel number 0 until an actual Channel # is mentioned. 
Tested with arcconf Version 7.0 (B18781) and Adaptec 2020ZCR. The GETCONFIG output of this version breaks the assumption that Status of Enclosure is the last data to parse (line 2320-2327 in the original check_raid.pl), so I accomodated that by matching known enclosure status information from the test data.