nfsstat: Add output for counts of new RPCs to the "-E" option

Add output to the "-E" option for new RPCs related
to NFSv4.1/4.2. Also, add output of the counts for
allocated layouts and the title for the "Client"
section (which was lost during a previous commit).

(cherry picked from commit 75c666197cc7574f6f0d48344f8725f72072fc84)