refactor test #6 to use [do_command]

data/test/scenarios/unit_test_6.cfg

@@ -22,14 +22,22 @@
             y = {Y}
             random_traits=false
         [/unit]
-        [issue_attack_command]
-            x1 = "$({X} + 1)"
-            y1 = {Y}
-            x2 = {X}
-            y2 = {Y}
-            attacker_weapon=0
-            defender_weapon=0
-        [/issue_attack_command]
+        [do_command]
+            [attack]
+                weapon = 0
+                defender_weapon = 0
+                attacker_type = Orcish Grunt
+                defender_type = Elvish Archer
+                [source]
+                    x = "$({X} + 1)"
+                    y = {Y}
+                [/source]
+                [destination]
+                    x = {X}
+                    y = {Y}
+                [/destination]
+            [/attack]
+        [/do_command]
         [store_unit]
             [filter]
                 id = {ID}