Determine previous and current it using all zip

```
    nbr_clients: [1, 1, 1]
    nbr_servers: [1, 1, 1]
    nbr_calls: [100, 50, 25]
    pause: [0.1, 0.2, 0.3]
```

nbr_calls and pause weren't taken into account in the previous iteration
calculation. The framework was misbehaving because, in the above, one new
client and server were started for each iteration.

This addresses #110

conf.yaml

@@ -1,16 +1,17 @@
 campaign:
   test_case_1:
-    nbr_clients: [1]
-    nbr_servers: [1]
-    nbr_calls: [100000]
-    pause: [0]
+    nbr_clients: [1, 1, 1]
+    nbr_servers: [1, 1, 1]
+    nbr_calls: [100, 50, 25]
+    pause: [0.1, 0.2, 0.3]
     call_type: ["rpc-call"]
     timeout: [3600]
     version: ["msimonin/ombt:singleton"]
     length: [1024]
     executor: ["threading"]
     driver: ["broker", "router"]
-    delay: [null, 0ms, 10ms, 20ms, 30ms, 40ms, 50ms, 60ms, 70ms, 80ms, 90ms, 100ms]
+    delay: [null, 0ms, 10ms, 50ms]
+    loss: [0, 0.5, 1]
     traffic: ["tc-10"]
   test_case_2:
     nbr_topics: [10]

orchestrator/campaign.py

@@ -138,8 +138,8 @@ def fix_1(parameters, current_parameters):
     {'nbr_clients': 1, 'nbr_servers': 4, 'topics': ['topic-0']}
     """
     # Note(msimonin): We may want to extend the get_current_value to all 'zip' elements
-    [p_clients, p_servers], [c_clients, c_servers] = get_current_values(
-        parameters, current_parameters, ["nbr_clients", "nbr_servers"])
+    [p_clients, p_servers, _, _], [c_clients, c_servers, _, _] = get_current_values(
+        parameters, current_parameters, ["nbr_clients", "nbr_servers", "nbr_calls", "pause"])
     current_parameters.update({"topics": ["topic-0"]})
     current_parameters.update({"nbr_clients": c_clients - p_clients})
     current_parameters.update({"nbr_servers": c_servers - p_servers})