LU-56 lnet: router-checker (RC) cleanup

LU-56 lnet: router-checker (RC) cleanup

This patched covered a couple of things:
- remove global router-checker data
  In current LNet we can have both global RC data and per-peer
  RC data, the later is only for asymmetrical router failure so far,
  however we can use per-peer RC data even asym_router_failure is
  disabled, it's just increase a little memory overhead but will
  simplify router checker.
  Also, I'm thinking that asym_router_failure is a nice feature and
  it should be enabled by default in the future.

- Code cleanup for router checker, again, it's still an intermediate
  patch for LNet SMP improvements, we need many code cleanup before
  we change locking mechanism of LNet.

Signed-off-by: Liang Zhen <liang@whamcloud.com>
Change-Id: I830e706ce5099f15f122b521f74b6dfcde443592
Reviewed-on: http://review.whamcloud.com/2930
Tested-by: Hudson
Reviewed-by: Doug Oucharek <doug@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Bobi Jam <bobijam@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>