LU-1095 debug: quiet unnecessary console chatter

LU-1095 debug: quiet unnecessary console chatter

Quiet warning when configuring non-default CPT partitions, since this
will happen whenever the module parameter is changed.  Only complain
if the number of partitions is more than the number of cores, or if
it is more than 4x the recommended number.

Running racer.sh provokes a lot of messages from mdd_readdir(),
because it is doing "ls" in a directory that has been unlinked.
This is legal under POSIX and should not generate a console message.

Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I33afab093e9a03324a579244ce5177708735e7cc
Reviewed-on: http://review.whamcloud.com/3894
Reviewed-by: Yu Jian <yujian@whamcloud.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Liang Zhen <liang@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>