Changed regex to be a bit more specific in what it matches against.  Also added a warning check to catch warnings in parted output and abort test run
Slight modification to the Warning check regex to only abort when the device we are testing generates a read-only warning
changed how we check for warnings
"automatic merge of lp:~bladernr/checkbox/1385821/ by tarmac [r=roadmr][bug=1395821][author=bladernr]"