Point to old instructions from /install and /upgrade

wiki/src/install.html

@@ -16,6 +16,18 @@
 
 <p>We will first ask you a few questions to choose your installation scenario and then guide you step by step.</p>
 
+<div class="note">
+
+<p>The following set of instructions is quite new. If you face problems
+following them:</p>
+
+<li>[[Report your problem.|support/talk]]</li>
+
+<li>Try following our old instructions for [[downloading|/download]] or
+[[installing|doc/first_steps]] instead.</li>
+
+</div>
+
 [[
   <div class="panel panel-primary">
     <div class="panel-heading">

wiki/src/upgrade.html

@@ -7,6 +7,18 @@
 
 <h1 class="text-center">Choose your <strong>manual upgrade</strong> scenario</h1>
 
+<div class="note">
+
+<p>The following set of instructions is quite new. If you face problems
+following them:</p>
+
+<li>[[Report your problem.|support/talk]]</li>
+
+<li>Try following our old instructions for [[downloading|/download]] or
+[[upgrading|doc/first_steps/upgrade]] instead.</li>
+
+</div>
+
 <div id="scenarios" class="row">
   <div class="col-md-6">