Remove Ruby warning due to assignment in conditional.

Remove Ruby warning due to assignment in conditional.
diff --git a/lib/discourse.rb b/lib/discourse.rb
index cab68f0..c78402b 100644
--- a/lib/discourse.rb
+++ b/lib/discourse.rb
@@ -358,7 +358,10 @@ module Discourse
   end
 
   def self.recently_readonly?
-    return false unless read_only = last_read_only[$redis.namespace]
+    if (read_only = last_read_only[$redis.namespace]).blank?
+      return false
+    end
+
     read_only > 15.seconds.ago
   end

GitHub sha: 704a1226

Why not do something like this instead?

read_only = last_read_only[$redis.namespace]
read_only.present? && read_only > 15.seconds.ago