cluster: Addition of new Scrubbing test

[amathuria]

Signed-off-by: Aishwarya Mathuria [email protected]

[amathuria]

For the scrubbing test, the name of the states like 'osdout' and 'osdin' can confuse other readers. Can this be changed to more appropriate states like for e.g., 'fillscrubpool', 'initscrub' to make it more intuitive?

Makes sense, I'll work on that and shift the scrub tests into a separate file.