change kernel spec placeholder name to 'Kernel'

IPython/html/templates/notebook.html

@@ -43,7 +43,7 b' class="notebook_app"'
 
 <span id="kernel_selector_widget" class="pull-right dropdown">
     <button class="dropdown-toggle" data-toggle="dropdown" type='button' id="current_kernel_spec">
-        <span class='kernel_name'>Python</span>
+        <span class='kernel_name'>Kernel</span>
         <span class="caret"></span> 
     </button>
     <ul id="kernel_selector" class="dropdown-menu">