compose: Only blur text boxes in compose box on hide.

Previously, we blurred all input/text boxes, including e.g. the search
box.  This probably won't impact normal operation, but this can be a
problem for our automated frontend tests which tend to have different
timing than real life.

(imported from commit ea84312bea2aae99d51b48cede0746e7a5b6e76e)

zephyr/static/js/compose.js

@@ -279,7 +279,7 @@ $(function () {
 });
 
 exports.hide = function () {
-    $('input, textarea, button').blur();
+    $('.message_comp > input, textarea, button').blur();
     $('.message_comp').slideUp(100,
                               function() { $('#compose').css({visibility: "hidden"});});
     notifications_bar.enable();