Fix premium items reroll on level change

Bug introduced a few commits ago in 1519e995cf

Fixes #4036

Source/diablo.cpp

@@ -1991,6 +1991,7 @@ void LoadGameLevel(bool firstflag, lvl_entry lvldir)
 		InitInv();
 		InitQuestText();
 		InitInfoBoxGfx();
+		InitStores();
 		InitAutomapOnce();
 		InitHelp();
 	}

Source/stores.cpp

@@ -2279,7 +2279,7 @@ void AddStoreHoldRepair(Item *itm, int8_t i)
 	storenumh++;
 }
 
-void SetupTownStores()
+void InitStores()
 {
 	ClearSText(0, STORE_LINES);
 	stextflag = STORE_NONE;
@@ -2293,7 +2293,10 @@ void SetupTownStores()
 
 	boyitem._itype = ItemType::None;
 	boylevel = 0;
+}
 
+void SetupTownStores()
+{
 	auto &myPlayer = Players[MyPlayerId];
 
 	int l = myPlayer._pLevel / 2;

Source/stores.h

@@ -101,8 +101,15 @@ extern int boylevel;
 extern Item boyitem;
 
 void AddStoreHoldRepair(Item *itm, int8_t i);
+
+/** Clears premium items sold by Griswold and Wirt. */
+void InitStores();
+
+/** Spawns items sold by vendors, including premium items sold by Griswold and Wirt. */
 void SetupTownStores();
+
 void FreeStoreMem();
+
 void PrintSString(const Surface &out, int margin, int line, const char *text, UiFlags flags, int price = 0);
 void DrawSLine(const Surface &out, int sy);
 void DrawSTextHelp();