rpcsvc: Ignore INODELK/ENTRYLK/LK for throttling

Problem:
When iozone is in progress, number of blocking inodelks sometimes becomes greater
than the threshold number of rpc requests allowed for that client
(RPCSVC_DEFAULT_OUTSTANDING_RPC_LIMIT). Subsequent requests from that client
will not be read until all the outstanding requests are processed and replied
to. But because no more requests are read from that client, unlocks on the
already granted locks will never come thus the number of outstanding requests
would never come down. This leads to a ping-timeout on the client.

Fix:
Do not account INODELK/ENTRYLK/LK for throttling

Change-Id: I59c6b54e7ec24ed7375ff977e817a9cb73469806
BUG: 1089470
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/7531
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>
Reviewed-by: Anand Avati <avati@redhat.com>