Added a simple check to prevent DoEnduranceUpkeep (1 sec persistent timer)

from constantly checking when client has no endurance drain effects.
This was running 24/7 for all classes.

zone/mob.cpp

@@ -391,6 +391,7 @@ Mob::Mob(const char* in_name,
 	for (int i = 0; i < HIGHEST_RESIST+2; i++) { Vulnerability_Mod[i] = 0; }
 
 	emoteid = 0;
+	endur_upkeep = false;
 }
 
 Mob::~Mob()