Hide the composebox's personal-message bar by default.

The form decides which fields to require based on whether
or not the personal-message bar is showing. Hide it by
default.

(Otherwise, both the 'Stream' and 'Huddle' prompts show up,
and you're obligated to fill out both of them.)

(imported from commit 13521ed5b7849f41c0335157d468f5e463c7f62d)

zephyr/static/styles/zephyr.css

@@ -235,6 +235,10 @@ img.profile_picture {
     filter:  alpha(opacity=40);
 }
 
+.zephyr_compose_table #personal-message {
+    display: none;
+}
+
 #connection-error {
     margin-top: 5px;
     display: none;