QA: Fix breakage on cluster initialization

The hypervisors are a list and need to be comma-separated.

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

qa/qa_cluster.py

@@ -97,7 +97,7 @@ def TestClusterInit(rapi_user, rapi_secret):
   cmd = [
     "gnt-cluster", "init",
     "--primary-ip-version=%d" % qa_config.get("primary_ip_version", 4),
-    "--enabled-hypervisors=%s" % qa_config.GetEnabledHypervisors(),
+    "--enabled-hypervisors=%s" % ",".join(qa_config.GetEnabledHypervisors()),
     ]
 
   for spec_type in ("mem-size", "disk-size", "disk-count", "cpu-count",