Core/Misc: Another batch of fixes for issues found by static analysis

src/server/scripts/Commands/cs_npc.cpp

@@ -252,7 +252,7 @@ public:
             return false;
         }
 
-        uint32 vendor_entry = vendor ? vendor->GetEntry() : 0;
+        uint32 vendor_entry = vendor->GetEntry();
 
         if (!sObjectMgr->IsVendorItemValid(vendor_entry, itemId, maxcount, incrtime, extendedcost, handler->GetSession()->GetPlayer()))
         {