Fix iteration in FFI::Table#free! method.

Author: jemc

lib/rabbitmq/ffi/ext/table.rb

@@ -23,7 +23,7 @@ def to_h(free=false)
       end
 
       def free!
-        self.each do
+        self.each do |entry|
           entry[:key].free!
           entry[:value].free!
         end