Fix transactions not rolling back properly

Fix test to actually check for the rollback happening

lib/sequelize.js

@@ -1142,18 +1142,18 @@ module.exports = (function() {
           var result = autoCallback(transaction);
           if (!result || !result.then) return reject(new Error('You need to return a promise chain/thenable to the sequelize.transaction() callback'));
 
-          result.then(function (result) {
+          return result.then(function (result) {
             return transaction.commit().then(function () {
               resolve(result);
             });
-          }).then(null, function (err) {
+          });
+        }).catch(function(err) {
           transaction.rollback().then(function () {
             reject(err);
           }, function () {
             reject(err);
           });
         });
-        }).catch(reject);
       };
 
       if (ns) {

test/integration/transaction.test.js

@@ -45,9 +45,13 @@ describe(Support.getTestDialectTeaser('Transaction'), function() {
       });
     });
     it('supports automatically rolling back with a thrown error', function() {
-      return expect(this.sequelize.transaction(function() {
+      var t;
+      return (expect(this.sequelize.transaction(function(transaction) {
+        t = transaction;
         throw new Error('Yolo');
-      })).to.eventually.be.rejected;
+      })).to.eventually.be.rejected).then(function() {
+        expect(t.finished).to.be.equal('rollback');
+      });
     });
     it('supports automatically rolling back with a rejection', function() {
       return expect(this.sequelize.transaction(function() {