security/rkhunter: Update to 1.4.4

While here, improve LICENSE

Changes: http://rkhunter.cvs.sourceforge.net/viewvc/rkhunter/rkhunter/files/CHANGELOG

PR: 220765
Submitted by: Lukasz Wasikowski <lukasz@wasikowski.net> (maintainer)
Approved by: garga (mentor, implicit)