This is garbage.
A) the "preferred" method only deals with the transparent_hugepage warning on mongod start. It does nothing for the defrag option and warning that continues to show up. So it's half a solution.
B) the alternate method of changing /etc/rc.local doesn't work because that runs in parallel to services starting. So it intermittently works on some machines and fails on others.
C) Change the darn default mongo init script to just start the process with the right settings. http://stackoverflow.com/questions/28911634/how-to-avoid-transparent-hugepage-defrag-warning-from-mongodb/29181918#29181918