Bug-Fix coverage output

output.py

 
 def coverage_output(lcov, bcov, length=None):
     if lcov is None or bcov is None:
+        length = length or len(STATUS_UNKNOWN)
         return (length - len(STATUS_UNKNOWN)) * ' ' + status_output(STATUS_UNKNOWN, termcolors.FAIL)
     elif lcov > 90:
         rv = termcolors.OKGREEN + '%3d%% (%3d%%)' % (lcov, bcov) + termcolors.ENDC