fix regression in resetting collapse to auto on collapse open. (+ add spec and rebuild)

docs/assets/css/bootstrap.css

@@ -4651,15 +4651,15 @@ a.badge:hover {
   -webkit-box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.15);
      -moz-box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.15);
           box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.15);
+  -webkit-box-sizing: border-box;
+     -moz-box-sizing: border-box;
+      -ms-box-sizing: border-box;
+          box-sizing: border-box;
   -webkit-transition: width 0.6s ease;
      -moz-transition: width 0.6s ease;
       -ms-transition: width 0.6s ease;
        -o-transition: width 0.6s ease;
           transition: width 0.6s ease;
-  -webkit-box-sizing: border-box;
-     -moz-box-sizing: border-box;
-      -ms-box-sizing: border-box;
-          box-sizing: border-box;
 }
 
 .progress-striped .bar {

docs/assets/js/bootstrap-collapse.js

@@ -95,7 +95,7 @@
   , transition: function (method, startEvent, completeEvent) {
       var that = this
         , complete = function () {
-            if (startEvent == 'show') that.reset()
+            if (startEvent.type == 'show') that.reset()
             that.transitioning = 0
             that.$element.trigger(completeEvent)
           }

docs/assets/js/bootstrap.js

@@ -507,7 +507,7 @@
   , transition: function (method, startEvent, completeEvent) {
       var that = this
         , complete = function () {
-            if (startEvent == 'show') that.reset()
+            if (startEvent.type == 'show') that.reset()
             that.transitioning = 0
             that.$element.trigger(completeEvent)
           }

js/bootstrap-collapse.js

@@ -95,7 +95,7 @@
   , transition: function (method, startEvent, completeEvent) {
       var that = this
         , complete = function () {
-            if (startEvent == 'show') that.reset()
+            if (startEvent.type == 'show') that.reset()
             that.transitioning = 0
             that.$element.trigger(completeEvent)
           }

js/tests/unit/bootstrap-collapse.js

@@ -37,4 +37,18 @@ $(function () {
           .collapse('show')
       })
 
+      test("should reset style to auto after finishing opening collapse", function () {
+        $.support.transition = false
+        stop();
+        $('<div class="collapse" style="height: 0px"/>')
+          .bind('show', function () {
+            ok(this.style.height == '0px')
+          })
+          .bind('shown', function () {
+            ok(this.style.height == 'auto')
+            start()
+          })
+          .collapse('show')
+      })
+
 })
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