fix test interpretation

tests/test_raid.py

@@ -23,8 +23,7 @@ def print_green(string):
 def check_raid(dev):
     cmd = 'mdadm -D %s' % dev
     status, output = subprocess.getstatusoutput(cmd)
-    print(output)
-    return status != 0
+    return status == 0 
 
 if os.path.isfile('/proc/mdstat'):
     all_ok = True