Update sysutils/kshutdown-kde4 to 4.0

• Update to 4.0
• Define the LICENSE
• Make qa.sh happy by adding some Qt and KDE dependencies
• Replace install/strip patch by upstreamed one by rakuco@ [1]

[1] https://sourceforge.net/p/kshutdown/patches/6/

Reviewed by: rakuco
Approved by: rakuco (mentor)
Differential Revision: https://reviews.freebsd.org/D7727