SotA S04: Update files to match faction renaming

data/campaigns/Secrets_of_the_Ancients/scenarios/04_Becalmed.cfg

@@ -133,7 +133,7 @@ The journey started well enough, but on the dawn following our departure, the wi
         hidden=yes
         color=orange
         [unit]
-            type=Khalif
+            type=Dunefolk
             x,y=12, 16
             facing=se
         [/unit]
@@ -529,7 +529,7 @@ The journey started well enough, but on the dawn following our departure, the wi
         [/kill]
         {OPEN_DOOR 14 13}
         [move_unit_fake]
-            type=Khalif
+            type=Dunefolk
             side=4
             x=12, 14
             y=16,  13

data/campaigns/Secrets_of_the_Ancients/units/Dunefolk.cfg

@@ -1,10 +1,10 @@
 #textdomain wesnoth-sota
 # used as passenger
 [unit_type]
-    id=Khalif
-    name= _ "Khalif"
+    id=Dunefolk
+    name= _ "Dunefolk"
     race=dunefolk
-    image="units/khalif.png"
+    image="units/dunefolk.png"
     hitpoints=30
     movement_type=smallfoot
     movement=5