mgr/cephadm: tolerate failure to update daemon caps

mgr/cephadm: tolerate failure to update daemon caps

If we're upgrading from 15.2.0, we may fail to update caps.  Instead of
failing the upgrade hard, warn to the log and continue.  This is less
than ideal, but the caps will get corrected the next time the daemon is
redeployed on the next upgrade, and most likely the previous caps will
continue to work (given they were presumably working before the upgrade).

Signed-off-by: Sage Weil <sage@newdream.net>