[test suite] Bug fix to not run an iptables Rijndael HMAC test on non-Linux systems
bumped version to 2.5.1
updated ChangeLog.git file to reflect changes from 2.5 -> 2.5.1
added 'Release: 2' for libfko RPM versioning (since libfko did not change from 2.5 -> 2.5.1)
updated ChangeLog.git file to reflect changes from 2.5 -> 2.5.1