Improve disk status detection
Improve disk status detection

The example in the test suite only checked `(F)`, but more statuses can
be found.

Based on:
https://github.com/torvalds/linux/blob/3e5c673f0d75bc22b3c26eade87e4db4f374cd34/drivers/md/md.c#L8257-L8269

riemann/riemann-tools,riemann/riemann-tools