Handle missing continuous queries in rake queries

Rakefile

@@ -63,7 +63,12 @@ task :queries do
     puts "Creating continuous query #{name}"
-    CLIENT.query("DROP CONTINUOUS QUERY #{name} ON #{db}")
+    begin
+      CLIENT.query("DROP CONTINUOUS QUERY #{name} ON #{db}")
+    rescue InfluxDB::QueryError => error
+      raise unless error.message.include?('query not found')
+    end
+
     CLIENT.query(query)
   end
 end