BaseTools: use existing shared variable

Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by: Yonghong Zhu <yonghong.zhu@intel.com>

BaseTools/Source/Python/Common/Misc.py

@@ -1922,7 +1922,7 @@ class DefaultStore():
             return (str(minvalue), self.DefaultStores[str(minvalue)])
     def GetMin(self,DefaultSIdList):
         if not DefaultSIdList:
-            return "STANDARD"
+            return TAB_DEFAULT_STORES_DEFAULT
         storeidset = {storeid for storeid, storename in self.DefaultStores.values() if storename in DefaultSIdList}
         if not storeidset:
             return ""