Merge pull request #261 from 0xcert/sload-sstore

eip-2200

Author: xpepermint

src/contracts/tokens/nf-token-metadata.sol

@@ -96,10 +96,7 @@ contract NFTokenMetadata is
   {
     super._burn(_tokenId);
 
-    if (bytes(idToUri[_tokenId]).length != 0)
-    {
-      delete idToUri[_tokenId];
-    }
+    delete idToUri[_tokenId];
   }
 
   /**

src/contracts/tokens/nf-token.sol

@@ -452,10 +452,7 @@ contract NFToken is
   )
     private
   {
-    if (idToApproval[_tokenId] != address(0))
-    {
-      delete idToApproval[_tokenId];
-    }
+    delete idToApproval[_tokenId];
   }
 
 }