Fix create_test_server for multiple create request

Currently create_test_server function assume that if
either 'min_count' or 'max_count' are present in kwargs then
request is for multiple create.

But that is not valid assumption. If 'min_count' and 'max_count'
are present and equal to 1 then it is single server create request.

Nova also set them default to 1 if they are not passed.
https://github.com/openstack/nova/blob/master/nova/compute/api.py#L1133

This commits checks if they are greater than 1 than only assume that
request is for multiple create server.

Change-Id: Ie4f45eb8481cd1aff55877cb7f8be327d548031e
diff --git a/tempest/common/compute.py b/tempest/common/compute.py
index 6e6ada8..d57bae3 100644
--- a/tempest/common/compute.py
+++ b/tempest/common/compute.py
@@ -55,10 +55,13 @@
     kwargs = fixed_network.set_networks_kwarg(
         tenant_network, kwargs) or {}
 
+    multiple_create_request = (max(kwargs.get('min_count', 0),
+                                   kwargs.get('max_count', 0)) > 1)
+
     if CONF.validation.run_validation and validatable:
         # As a first implementation, multiple pingable or sshable servers will
         # not be supported
-        if 'min_count' in kwargs or 'max_count' in kwargs:
+        if multiple_create_request:
             msg = ("Multiple pingable or sshable servers not supported at "
                    "this stage.")
             raise ValueError(msg)
@@ -112,7 +115,7 @@
 
     # handle the case of multiple servers
     servers = []
-    if 'min_count' in kwargs or 'max_count' in kwargs:
+    if multiple_create_request:
         # Get servers created which name match with name param.
         body_servers = clients.servers_client.list_servers()
         servers = \