Inconsistent output in memory usage reporting
When there is swap warning, it looks like;
#19.4 memory_usage test for mizumushi: Warning Usage: 72%, swap is not available
In other cases, it looks like;
#21.3 memory_usage test for miyako: OK! Total: 1.94 GB, Used: 0.72 GB, free: 1.22 GB Usage: 38%