Fix remaining uses of transition-duration without time units

Commit 8be3c5ed21 changed the CSS parser
to only accept values with explicit time units.

js/ui/panel.js

@@ -852,7 +852,7 @@ const PanelCorner = new Lang.Class({
 
             // The corner doesn't support theme transitions, so override
             // the .panel-button default
-            button.style = 'transition-duration: 0';
+            button.style = 'transition-duration: 0ms';
         }
     },
 

tests/testcommon/test.css

@@ -98,7 +98,7 @@ stage {
     background-color: #333;
     border: 2px solid black;
     border-radius: 8px;
-    transition-duration: 1000; /* One second */
+    transition-duration: 1s;
 }
 
 #transition-container:hover .transition-label {