LU-3243 utils: print value in lctl set_param error

LU-3243 utils: print value in lctl set_param error

Print out the invalid value that was trying to be set via
"lctl set_param parameter=value", so that it is more clear
what is going wrong when this is being called from a script.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: Iebd0ae70dc9dbd378775339ccba2ab90a97d1093
Reviewed-on: http://review.whamcloud.com/6205
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Emoly Liu <emoly.liu@intel.com>
Reviewed-by: John Hammond <johnlockwoodhammond@gmail.com>
Reviewed-by: Prakash Surya <surya1@llnl.gov>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>