Remove warning during testing

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: alloy-1.0.0, alloy-2.0.0, alloy-3.0.0, portal-1.0.0, portal-2.0.0, portal-3.0.0, bridge-impl-2.0.0, bridge-impl-3.0.0, showcase-2.0.0, bridge-impl-4.0.0, showcase-3.0.0
• Fix Version/s: alloy-1.0.1, alloy-2.0.1, portal-1.0.1, portal-2.0.1, bridge-impl-2.1.0, bridge-impl-3.1.0, bridge-impl-4.1.0, portal-3.0.1, showcase-2.0.1, showcase-3.0.1, alloy-3.0.1
• Component/s: JSF Showcase, Liferay Faces Alloy / Showcase / Tests, Liferay Faces Bridge Impl / Demos / Tests, Liferay Faces Portal / Demos / Tests
• Labels: None

Add property to pom to prevent these warnings during testing:

[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent! The file encoding for reports output files should be provided by the POM property ${project.reporting.outputEncoding}.
[INFO] 
[INFO] --- maven-failsafe-plugin:2.19.1:verify (selenium-tests) @ com.liferay.faces.demo.jsf.showcase.webapp ---
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent! The file encoding for reports output files should be provided by the POM property ${project.reporting.outputEncoding}.