#177591: cannot clean & build a jee6 web project with ws client

Please review a fix for:
https://netbeans.org/bugzilla/show_bug.cgi?id=177591

Description:
Project can not be built if WS Client is created in Maven Java EE 6 web 
project.
This is caused by the fact that WS Client wizard overwrites 
maven-war-plugin version in pom.xml file

Impact:
This affects Java EE 6 maven web project containing WS Client, created 
by Netebans  wizard

Fix: The plugin version isn't overwritten for existing plugin in pom.xml 
file
https://netbeans.org/bugzilla/show_bug.cgi?id=177591

Risk: easy fix, no risk

Reviewers: Lukas Jungmann, Petr Hejl.

Thanks