wallet: Remove unused boost::thread_interrupted

FindWalletTx is only called by zapwallet, which is never called in a
boost::thread

src/wallet/walletdb.cpp

@@ -874,11 +874,7 @@ DBErrors WalletBatch::FindWalletTx(std::vector<uint256>& vTxHash, std::list<CWal
             }
         }
         pcursor->close();
-    }
-    catch (const boost::thread_interrupted&) {
-        throw;
-    }
-    catch (...) {
+    } catch (...) {
         result = DBErrors::CORRUPT;
     }