Update to debhelper compat 11.

debian/compat

@@ -1 +1 @@
-9
+11

debian/control

@@ -2,7 +2,7 @@ Source: lubuntu-default-settings
 Section: x11
 Priority: optional
 Maintainer: Julien Lavergne <gilir@ubuntu.com>
-Build-Depends: debhelper (>= 9), intltool
+Build-Depends: debhelper (>= 11), intltool
 Standards-Version: 3.9.5
 Homepage: https://launchpad.net/~lubuntu-desktop
 Vcs-Browser: https://git.launchpad.net/lubuntu-default-settings?h=master

debian/rules

@@ -5,5 +5,5 @@
 override_dh_auto_build:
 	$(MAKE) DESTDIR=$(CURDIR)/debian/tmp
 
-override_dh_install:
-	dh_install --fail-missing
+override_dh_missing:
+	dh_missing --fail-missing