LU-2059 mgs: don't fail on missing params log

The mgc_process_cfg_log() fails if 'params' log is not
accessinble and has no local copy. In fact that log is
optional and may be just empty.

Patch allows 'params' log to be empty and checks also for
'params' log in other places to avoid wrong error messages.
There was also deprecated code in mgs_write_log_direct_all()
which creates lustre-params log which is not used by anyone now.
Third change is removal of exceptions in conf-sanity.sh and
insanity.sh related to LU-2059

The only exception is insanity test_1 which is still failed due
to other reason.

Signed-off-by: Mikhail Pershin <mike.pershin@intel.com>
Change-Id: I1ad024a87b0a10665f9669fa8ff7cca2d07a09fe
Reviewed-on: http://review.whamcloud.com/10311
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
LU-2059 mgs: fix a bug in mgs_llog_open

- don't calculate len for NULL ptr
- check the logname is PARAMS_FILENAME inside 'if (ptr == NULL ...)
clause so all cases with NULL ptr will end there.

Signed-off-by: Mikhail Pershin <mike.pershin@intel.com>
Change-Id: Ib87ecb3245833fc8f9d069898a1b80c44bbfd9f0
Reviewed-on: http://review.whamcloud.com/10589
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>