Automatically disable apache status module when
apache hardening is turned on.
sync charm-helpers for apache hardening fixes.
Change-Id: Idb114f4c37d5a570b352dbd43035cd737a658a1d
Closes-Bug: #1710917
Add charmhelpers.contrib.hardening and calls to install,
config-changed, upgrade-charm and update-status hooks. Also
add new config option to allow one or more hardening
modules to be applied at runtime.
Change-Id: I3009f6f20d9e3524d5396b9828610e6586692827