qa: skip gnt-backup for file instances

Note that this fixes the "current issue" but doesn't fix the underlying
problem. :/

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michele Tartara <mtartara@google.com>

qa/ganeti-qa.py

@@ -364,7 +364,11 @@ def RunExportImportTests(instance, inodes):
   @param inodes: current nodes of the instance
 
   """
-  if qa_config.TestEnabled("instance-export"):
+  # FIXME: export explicitly bails out on file based storage. other non-lvm
+  # based storage types are untested, though. Also note that import could still
+  # work, but is deeply embedded into the "export" case.
+  if (qa_config.TestEnabled("instance-export") and
+      instance.disk_template != constants.DT_FILE):
     RunTest(qa_instance.TestInstanceExportNoTarget, instance)
 
     pnode = inodes[0]