LU-2149 llog: lctl to work with llogs from command line

LU-2149 llog: lctl to work with llogs from command line

- mgs_list_logs() is introduced to get all of configs and
  mgs_iocontrol handles that and also cancel/remove ioctl
- remove obsoleted code from mdc_iocontrol
- add handler to list llog catalogs from mdt_iocontrol too
- lctl llog_print outputs records in YAML format

Signed-off-by: Amir Shehata <amir.shehata@intel.com>
Change-Id: Ic6e392403da18a2d7578aafdddf01007c3b3c30e
Reviewed-on: http://review.whamcloud.com/4254
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>