tests/vm: Increase timeout waiting for VM to boot to 5 minutes

The VM tests currently have a timeout of 2 minutes for trying
to connect to ssh. Since the guest VM has to boot from cold
to the point of accepting inbound ssh during this time, if the
host machine is heavily loaded it can spuriously time out.
Increase the timeout from 2 to 5 minutes.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Acked-by: NFam Zheng <famz@redhat.com>
Message-id: 20180823112153.15279-1-peter.maydell@linaro.org

tests/vm/basevm.py

@@ -176,7 +176,7 @@ class BaseVM(object):
             raise Exception("Cannot find ssh port from 'info usernet':\n%s" % \
                             usernet_info)
 
-    def wait_ssh(self, seconds=120):
+    def wait_ssh(self, seconds=300):
         starttime = datetime.datetime.now()
         guest_up = False
         while (datetime.datetime.now() - starttime).total_seconds() < seconds: