BugLink: http://bugs.launchpad.net/bugs/1764794
OldBugLink: http://bugs.launchpad.net/bugs/1766391

There's a typo in the headers postinst which prevents triggering
of dkms builds on installation. Change this to use the correct
path, /etc/kernel/header_postinst.d.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>