Switching from empty string to empty dict

We had multiple fields that would reference either an empty strig or
empty dict, which would cause indexing errors on Elastic. This commit is
to create a standard of empty dict for args.

Closes bug 1678107

Change-Id: Id5b2ad924bac4f1b4aee74e9d6f407f9d5e2ca10

rally/neutron/neutron-create-list-network-cc.yml

@@ -5,7 +5,7 @@
   NeutronNetworks.create_and_list_networks:
     -
       args:
-        network_create_args: ""
+        network_create_args: {}
       runner:
         concurrency: {{concurrency}}
         times: {{times}}

rally/neutron/neutron-create-list-port-cc.yml

@@ -6,7 +6,7 @@
   NeutronNetworks.create_and_list_ports:
     -
       args:
-        network_create_args: ""
+        network_create_args: {}
         ports_per_network: {{ports_per_network}}
       runner:
         concurrency: {{concurrency}}

rally/neutron/neutron-create-list-router-cc.yml

@@ -7,8 +7,8 @@
   NeutronNetworks.create_and_list_routers:
     -
       args:
-        network_create_args: ""
+        network_create_args: {}
-        subnet_create_args: ""
+        subnet_create_args: {}
         subnet_cidr_start: "10.0.0.0/16"
         subnets_per_network: {{subnets_per_network}}
         router_create_args: {{ router_create_args }}

rally/neutron/neutron-create-list-security-group-cc.yml

@@ -5,7 +5,7 @@
   NeutronSecurityGroup.create_and_list_security_groups:
     -
       args:
-        security_group_create_args: ""
+        security_group_create_args: {}
       runner:
         concurrency: {{concurrency}}
         times: {{times}}

rally/neutron/neutron-create-list-subnet-cc.yml

@@ -6,8 +6,8 @@
   NeutronNetworks.create_and_list_subnets:
     -
       args:
-        network_create_args: ""
+        network_create_args: {}
-        subnet_create_args: ""
+        subnet_create_args: {}
         subnet_cidr_start: "1.1.0.0/30"
         subnets_per_network: {{subnets_per_network}}
       runner: