#7317 ENOSPC and OSD epoch barrier handling


Related:
https://github.com/ceph/ceph-qa-suite/pull/225
https://github.com/ceph/ceph-client/pull/7
This looks like user documentation rather than implementation, which I believe should be in the header (and which we sort-of mostly do in our codebase). :)
See eg http://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Function_Comments