nfs4_op_sequence: Always V after P

The code had several logic paths where a request could leave an nfs4.1
"session slot" locked (DRC replay).  Any future request that hit that slot would
then lock up forever.  Once the server runs out of worker threads it
stops responding to anything.  The linux nfs client will trivially hit
this bug with "sec=krb5i", once its kerberos ticket expires.

Signed-off-by: Marcus Watts <mdw@linuxbox.com>
thread_delay_ms - really, milliseconds != nanoseconds.

This function was supposed to wait for N milliseconds. The sub-second
logic was busted, so it was actually waiting for N nanoseconds.

There are several cases in nfs_rpc_getreq_ng() that are supposed to wait
( thread_delay_ms(5); ) when bad things happen - the result is instead
of quietly waiting for things to get better, they do a "busy wait"
consuming CPU, which certainly doesn't help the bad stuff get better.

Signed-off-by: Marcus Watts <mdw@linuxbox.com>