wallet2: fix ring reuse breaking when using histogram

src/wallet/wallet2.cpp

@@ -7143,6 +7143,9 @@ void wallet2::get_outs(std::vector<std::vector<tools::wallet2::get_outs_entry>>
           break;
         }
       }
+      bool use_histogram = amount != 0 || !has_rct_distribution;
+      if (!use_histogram)
+        num_outs = rct_offsets[rct_offsets.size() - CRYPTONOTE_DEFAULT_TX_SPENDABLE_AGE];
 
       // make sure the real outputs we asked for are really included, along
       // with the correct key and mask: this guards against an active attack