LU-2156 misc: too noisy messages are suppressed

LU-2156 misc: too noisy messages are suppressed

- number of messages leading to confusion and adding no
  useful information to the customers are suppressed.

- remove KEY_REVIMP_UPD - it's not used with OFD

Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Change-Id: I9679b786354a2f4b52c5c13e0e2ec98a5a5b86a9
Reviewed-on: http://review.whamcloud.com/4261
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Mike Pershin <tappro@whamcloud.com>
Reviewed-by: Prakash Surya <surya1@llnl.gov>