Merge pull request #3409 from trociny/wip-osd_pool_flags

osd: new pool safeguard flags: nodelete, nopgchange, nosizechange

Reviewed-by: Sage Weil <sage@redhat.com>

diff --cc qa/workunits/cephtool/test.sh
Simple merge

diff --cc src/common/config_opts.h
Simple merge

diff --cc src/mon/MonCommands.h
Simple merge