adding filter to detect Shellshock attack attempts against bash scripts through apache.  See http://seclists.org/oss-sec/2014/q3/650
adding jail conf for shellshock filter
adding test case, changelog and thanks entries for apache shellshock filter
forgot to add test case to last commit
Merge pull request #818 from slowriot/master

adding filter to detect Shellshock attack attempts with Apache
tests: define CONFIG_DIR in utils.
Merge pull request #813 from schaal/tests-configdir-env-variable

tests: Add function to utils to calculate CONFIG_DIR