Update Ceph FSAL configuration to match others.

*	better error returns and diagnostics
*	configuration: some configuration stubs
*	cosmetic: reformatting, comments

There are some ceph functions here that are not present in any release
version of ceph.  This marks them "if 0" for future work.  This isn't
useful without pnfs / ds, which this code doesn't (yet) support.

Use a default case for the enumeration types,
remove the now redundant explicit "false" cases.

Revise the configuration logic to better match the pattern used
in all the other fsals.  No more silly cases in fs_supports()!

Also: create files, symlinks, and directories with the permissions
actually requested, and support "fs_umask" to reduce those permissions
like the other fsals do.

Signed-off-by: William Allen Simpson <bill@cohortfs.com>
Signed-off-by: Marcus Watts <mdw@cohortfs.com>