Add a comment describing the "-i" flag, when it is needed and why.
Signed-Off-By: Jon Mason <jon@opengridcomputing.com>
$ mount.rnfs <IPoIB-server-name-or-address>:/<export> /mnt -o proto=rdma,port=20049
+ NOTE: For kernels < 2.6.23, the "-i" flag must be passed into mount.rnfs.
+ This option allows the mount command to ignore the kernel version check. If
+ not disabled, the check will prevent passing arguments to the kernel and not
+ allow the updated version of NFS to accept the "rdma" NFS option.
+
To verify that the mount is using RDMA, run "cat /proc/mounts" and check
the "proto" field for the given mount.