pdu->timeout needs to be uint64_t

pdu->timeout is the timeout for for the pdu using the unix epoch but
expressed in ms, not seconds.
As such it must be 64 bit as on 32 bit we would have already wrapped the
timer.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>

include/libnfs-private.h

@@ -177,7 +177,7 @@ struct rpc_pdu {
 #define PDU_DISCARD_AFTER_SENDING 0x00000001
         uint32_t flags;
 
-	long timeout;
+	uint64_t timeout;
 };
 
 void rpc_reset_queue(struct rpc_queue *q);