LU-2456 lnet: Dynamic LNet Configuration (DLC) dynamic routing

LU-2456 lnet: Dynamic LNet Configuration (DLC) dynamic routing

This is the second patch of a set of patches that enables DLC.

This patch adds the following features to LNET.  Currently these
features are not driven by user space.
- Enabling Routing on Demand.  The default number of router
  buffers are allocated.
- Disable Routing on demand. Unused router buffers are freed and
  used router buffers are freed when they are no longer in use.
  The following time routing is enabled the default router buffer
  values are used.  It has been decided that remembering the
  user set router buffer values should be remembered and re-set
  by user space scripts.
- Increase the number of router buffers on demand, by allocating
  new ones.
- Decrease the number of router buffers.  Exccess buffers are freed
  if they are not in use.  Otherwise they are freed once they are
  no longer in use.

Signed-off-by: Amir Shehata <amir.shehata@intel.com>
Change-Id: Id07d4ad424d8f5ba72475d4149380afe2ac54e77
Reviewed-on: http://review.whamcloud.com/9831
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Doug Oucharek <doug.s.oucharek@intel.com>
Reviewed-by: Liang Zhen <liang.zhen@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>