ZF-6689: Functions without return parameter are not translated to One-Way Operations

Description

When there's no Docblock @return-statement for a function it should be translated to a One-Way operation as described here: http://www.w3.org/TR/wsdl#_one-way

Instead there is a reference to a missing message "OperationResponse".

Comments

Fixed in trunk, won't be merged into 1.8 release branch because although a bugfix this might induce some changes into existing production code.