upgrade: consider all 'active+clean' states as valid pgs

upgrade: consider all 'active+clean' states as valid pgs

In cluster with a large number of PGs, it can be expected some of them
scrubbing, it's a normal operation.
Preventing from scrubbing operation force to set noscrub flag before a
rolling update which is a problem because it pauses an important data
integrity operation until the end of the rolling upgrade.

This commit allows an upgrade even while PGs are scrubbing.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1616066
Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>