Replaced all occurrences of 'on' by 'yes'.

(2 in campaigns, 2 in mp maps.)

data/campaigns/Heir_To_The_Throne/scenarios/19c_Cliffs_of_Thoria.cfg

@@ -270,7 +270,7 @@
             [/modifications]
             {IS_LOYAL}
             [status]
-                poisoned=on
+                poisoned=yes
             [/status]
         [/unit]
         [message]

data/campaigns/The_Rise_Of_Wesnoth/scenarios/09_Fallen_Lich_Point.cfg

@@ -105,7 +105,7 @@
 
 #define PETRIFIED
     [status]
-        petrified=on
+        petrified=yes
     [/status]
 #enddef
 

data/multiplayer/scenarios/2p_Caves_of_the_Basilisk.cfg

@@ -10,7 +10,7 @@
         random_traits=no
 
         [status]
-            petrified=on
+            petrified=yes
         [/status]
 
         [modifications]

data/multiplayer/scenarios/2p_Sullas_Ruins.cfg

@@ -14,7 +14,7 @@
         random_traits=no
 
         [status]
-            petrified=on
+            petrified=yes
         [/status]
 
         [modifications]

data/scenario-test.cfg

@@ -83,7 +83,7 @@ Xu          , Xu          , Qxu         , Qxu         , Ql          , Ql
             generate_name=yes
             hitpoints=4
             [status]
-                petrified=on
+                petrified=yes
             [/status]
             overlays="wesnoth-icon.png~CROP(10,10,20,20)"
         [/unit]
@@ -107,7 +107,7 @@ Xu          , Xu          , Qxu         , Qxu         , Ql          , Ql
             generate_name=yes
             hitpoints=9
             [status]
-                poisoned=on
+                poisoned=yes
             [/status]
         [/unit]
         [unit]