LU-15900 hsm: don't return error on state change during mount

LU-15900 hsm: don't return error on state change during mount

HSM coordinator is started in stopped state always, but
mount may have hsm_control parameters 'disabled'. Such
parameter cause wrong state change so mount would fail
with error.

Treat parameter change from 'stopping/stopped' to 'disabled'
as not critical error, keep state unchanged and report
no error back to a caller.

Signed-off-by: Mikhail Pershin <mpershin@whamcloud.com>
Change-Id: I9d1366423391971b9511c46b6aed39d21ebf637c