Fix iperf test and make server/client jobs to write to different result log directory.

server/tests/netpipe/netpipe.py

 from autotest_lib.server import autotest, hosts, subcommand, test
 from autotest_lib.server import utils
 
 class netpipe(test.test):
     version = 2
 
     def run_once(self, pair, buffer, upper_bound, variance):
         print "running on %s and %s\n" % (pair[0], pair[1])
 
         # Designate a platform label for the server side of tests.
@@ skipping 20 matching lines @@
                             "client_ip='%s', role='%s', bidirectional=True, ",
                             "buffer_size=%d, upper_bound=%d,"
                             "perturbation_size=%d)"])
 
         server_control_file = template % (server.ip, client.ip, 'server',
                                           buffer, upper_bound, variance)
         client_control_file = template % (server.ip, client.ip, 'client',
                                           buffer, upper_bound, variance)
 
         server_command = subcommand.subcommand(server_at.run,
-                                    [server_control_file, server.hostname])
+                                    [server_control_file, server.hostname],
+                                    subdir='server')
         client_command = subcommand.subcommand(client_at.run,
-                                    [client_control_file, client.hostname])
+                                    [client_control_file, client.hostname],
+                                    subdir='client')
 
         subcommand.parallel([server_command, client_command])
 
         for m in [client, server]:
             status = m.run('iptables -L')
             if not status.exit_status:
                 m.enable_ipfilters()