Increase ping timeout from 60 to 120 seconds

The Cirros image only sends out three DHCPDISCOVERs with 60 second
waits between. The ovs_neutron_agent may not have the port wired in
time for the first one, and with ping_timeout=60 the test will be
terminated before the second one is sent. This patch increases the
timeout to 120 seconds to prevent that.

Change-Id: I03fcec50b91fd89ad64e16fce82f9211c2e086a1
Partial-Bug: 1253896
diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index bb9a68e..21c8506 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -226,7 +226,7 @@
 
 # Timeout in seconds to wait for ping to succeed. (integer
 # value)
-#ping_timeout=60
+#ping_timeout=120
 
 # Timeout in seconds to wait for authentication to succeed.
 # (integer value)
diff --git a/tempest/config.py b/tempest/config.py
index d529965..5a9199d 100644
--- a/tempest/config.py
+++ b/tempest/config.py
@@ -147,7 +147,7 @@
                default='root',
                help="User name used to authenticate to an instance."),
     cfg.IntOpt('ping_timeout',
-               default=60,
+               default=120,
                help="Timeout in seconds to wait for ping to "
                     "succeed."),
     cfg.IntOpt('ssh_timeout',