rados.py, ceph: add timeout for run_in_thread and selected callers

Signed-off-by: Dan Mick <dan.mick@inktank.com>
Makefile.am: Move cmdparse to libcommon

Signed-off-by: Dan Mick <dan.mick@inktank.com>
admin_socket and all users: command-descriptor support

add cmddesc to all register_command calls, and add a class and
command to return all the command descriptors as is done for
monitor, osd tell, and pg pgid commands.

Signed-off-by: Dan Mick <dan.mick@inktank.com>
ceph: admin_socket() returns data rather than printing.

Preparation for use in daemon command validation/help enumeration

Signed-off-by: Dan Mick <dan.mick@inktank.com>
wip: ceph: print help for osd.0, mon.a, mds.a daemon commands

Issues:
1) ignore commands with no help text, as does daemon help?
2) come up with daemon names from running config somehow
3) do we *want* to do all, always?  Maybe

	--help	for 'normal' mon commands, mon daemon commands
	--help-osd for osd tell, pg, osd daemon commands
	--help-mds for mds daemon commands
	--help-all for all the above
?

Signed-off-by: Dan Mick <dan.mick@inktank.com>