install: fix purge arg

Signed-off-by: Sage Weil <sage@inktank.com>
purgedata: new command to purge /var/lib/ceph data

The package removal doesn't remove cluster data; this command will.  The
user should be careful doing this, of course.

Signed-off-by: Sage Weil <sage@inktank.com>
osd: fix 'activate ...' debug print

Signed-off-by: Sage Weil <sage@inktank.com>
purgedata: fix

add missing ;

Signed-off-by: Sage Weil <sage@inktank.com>
Send log msgs to file '{cluster}.log' as well as console.

Default log level is INFO to console, DEBUG to logfile
--verbose changes console log level to DEBUG as well
logfile gets timestamp modulename level msg, console gets just msg

Fixes: #4468
Signed-off-by: Dan Mick <dan.mick@inktank.com>
do not default to verbose

Signed-off-by: Dan Mick <dan.mick@inktank.com>
disk: new command, with list, prepare, activate

Create new disk command.

Change 'osd prepare ...' to 'disk prepare ...'
Change 'osd activate ...' to 'disk activate ...'
Move 'zapdisk HOST' to 'disk zap HOST'
Add 'disk list HOST'

This keeps the osd command simple and clean, and makes 'disk list' make
sense.

The HOST vs HOST:DISK is slightly weird still.  Oh well.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>