initialize /proc/sys/vm/memory_failure_early_kill
update distro checker
some tweak on thp testcase
add -h option on mceinj.sh
fix run-huge-thp.sh to run correctly on v3.13-rc4
fix run-test-hugetlb.sh to run correctly on v3.13-rc4
fix run-test-ksm.sh to run correctly on v3.13-rc4
fix run-test-sample.sh to run correctly on v3.13-rc4
small updates for RHEL7 testing