if no callback, don't try to call callback ya goof

docs/assets/js/bootstrap-modal.js

@@ -171,6 +171,8 @@
 
           this.$backdrop.addClass('in')
 
+          if (!callback) return
+
           doAnimate ?
             this.$backdrop.one($.support.transition.end, callback) :
             callback()

docs/assets/js/bootstrap.js

@@ -969,6 +969,8 @@
 
           this.$backdrop.addClass('in')
 
+          if (!callback) return
+
           doAnimate ?
             this.$backdrop.one($.support.transition.end, callback) :
             callback()

js/bootstrap-modal.js

@@ -171,6 +171,8 @@
 
           this.$backdrop.addClass('in')
 
+          if (!callback) return
+
           doAnimate ?
             this.$backdrop.one($.support.transition.end, callback) :
             callback()