TSG: remove not anymore needed macro

The alternative message was needed for the scenario where Deoran is not on the map.
This has been removed, and in the other which is left (S8b), both units won't be around.

The only places left for this message is the last level in path B and the lasts ind path A
It's not necessary that there is an alternative message, this is only used there because
it exists already – both would fit.

[ci skip]

data/campaigns/The_South_Guard/utils/sg_deaths.cfg

@@ -5,8 +5,6 @@
 
 #define SG_DEATHS_HYLAS_LATE
 #enddef
-#define SG_DEATHS_JAREK_ALTERNATIVE
-#enddef
 
 #endif
 
@@ -101,7 +99,7 @@
     [filter]
         id=Jarek
     [/filter]
-#ifndef SG_DEATHS_JAREK_ALTERNATIVE
+#ifndef SG_DEATHS_LAST_LEVEL
     [message]
         speaker=unit
         message= _ "Far from home I fall — but not in vain! Defend our people, Deoran!"
@@ -109,6 +107,7 @@
 #else
     [message]
         speaker=unit
+        # po: Alternative message used in the last scenario.
         message= _ "Far from home I fall — but not in vain!"
     [/message]
 #endif
@@ -121,14 +120,8 @@
 
 #ifdef SG_DEATHS_LAST_LEVEL
 #undef SG_DEATHS_LAST_LEVEL
-#undef SG_DEATHS_HYLAS_LATE
-#undef SG_DEATHS_JAREK_ALTERNATIVE
 #endif
 
 #ifdef SG_DEATHS_HYLAS_LATE
 #undef SG_DEATHS_HYLAS_LATE
 #endif
-
-#ifdef SG_DEATHS_JAREK_ALTERNATIVE
-#undef SG_DEATHS_JAREK_ALTERNATIVE
-#endif