Fix for site:sshdeploy

[Sascha-Matthias Kulawik]

Hello,
 
I'd like to propose a fix for the site:sshdeploy goal:
at me the 
maven.site.tar.options=xUvf
returns an unlink error during etraction.
So i would propose 

maven.site.tar.options=--recursive-unlink -xvf

as default option.

Regards,

Sascha