Add a QA option to disable reboots during burnin

Since we have seen cases where (repeated) reboots are not supported
(e.g. Xen 3.4+), we need to be able to control this in the QA
configuration.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

qa/qa-sample.json

@@ -95,7 +95,8 @@
     "burnin-disk-template": "drbd",
     "burnin-in-parallel": false,
     "burnin-check-instances": false,
-    "burnin-rename": "xen-test-rename"
+    "burnin-rename": "xen-test-rename",
+    "burnin-reboot": true
   },
 
   "# vim: set syntax=javascript :": null

qa/qa_cluster.py

@@ -231,6 +231,7 @@ def TestClusterBurnin():
   parallel = options.get('burnin-in-parallel', False)
   check_inst = options.get('burnin-check-instances', False)
   do_rename = options.get('burnin-rename', '')
+  do_reboot = options.get('burnin-reboot', True)
 
   # Get as many instances as we need
   instances = []
@@ -260,6 +261,8 @@ def TestClusterBurnin():
         cmd.append('--http-check')
       if do_rename:
         cmd.append('--rename=%s' % do_rename)
+      if not do_reboot:
+        cmd.append('--no-reboot')
       cmd += [inst['name'] for inst in instances]
       AssertEqual(StartSSH(master['primary'],
                            utils.ShellQuoteArgs(cmd)).wait(), 0)