tablist is not under a menubar (#6345)

Author: Scott Bommarito

src/NuGetGallery/Views/Shared/Gallery/Header.cshtml

@@ -73,7 +73,7 @@
                              @ViewHelpers.ImageFallback(Url.Absolute("~/Content/gallery/img/logo-header-94x29.png")) />
                     </a>
                 </div>
-                <div id="navbar" class="navbar-collapse collapse" role="menubar">
+                <div id="navbar" class="navbar-collapse collapse">
                     <ul class="nav navbar-nav" role="tablist">
                         @DisplayNavigationItem("Packages", Url.PackageList())
                         @DisplayNavigationItem("Upload", Url.UploadPackage())