The nfsstat program reads /proc/net/rpc/* files to gets info about

The nfsstat program reads /proc/net/rpc/* files to gets info about
calls. This info is output as unsigned numbers (at least on any
relatively recent kernel). When nfsstat prints these numbers, they are
printed as signed integers. When the call counters reach 2^31, things
start being printed as negative numbers.

This patch changes nfsstat to read and print all counters as unsigned
integers. Tested by hacking up a kernel to initialize call counters to
2^31+1.

Thanks to Takafumi Miki for the initial version of this patch.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve Dickson <steved@redhat.com>