Use dh_installdeb maintscript support (#659794)

Use maintscript support in dh_installdeb rather than writing out
dpkg-maintscript-helper commands by hand. We now simply Pre-Depend on a
new enough version of dpkg rather than using 'dpkg-maintscript-helper
supports' guards, leading to more predictable behaviour on upgrades.

debian/control

@@ -14,6 +14,7 @@ Vcs-Git: git://git.debian.org/collab-maint/tmux.git
 
 Package: tmux
 Architecture: any
+Pre-Depends: ${misc:Pre-Depends}
 Depends: ${shlibs:Depends}, ${misc:Depends}
 Description: terminal multiplexer
  tmux enables a number of terminals (or windows) to be accessed and

debian/maintscript

@@ -0,0 +1 @@
+rm_conffile /etc/init.d/tmux-cleanup 1.4-6

debian/postinst

@@ -2,10 +2,6 @@
 
 set -e
 
-if dpkg-maintscript-helper supports rm_conffile; then
-    dpkg-maintscript-helper rm_conffile /etc/init.d/tmux-cleanup 1.4-6 -- "$@"
-fi
-
 if [ "$1" = "configure" ]; then
     if [ -z "$2" ] || dpkg --compare-versions "$2" lt "1.5-3"; then
 	add-shell /usr/bin/tmux

debian/postrm

@@ -2,10 +2,6 @@
 
 set -e
 
-if dpkg-maintscript-helper supports rm_conffile; then
-    dpkg-maintscript-helper rm_conffile /etc/init.d/tmux-cleanup 1.4-6 -- "$@"
-fi
-
 if [ "$1" = "remove" ]; then
     remove-shell /usr/bin/tmux
 fi

debian/preinst

@@ -7,8 +7,4 @@ if [ "$1" = "upgrade" ] && dpkg --compare-versions "$2" 'lt' "1.5-2"; then
     update-rc.d -f tmux-cleanup remove >/dev/null
 fi
 
-if dpkg-maintscript-helper supports rm_conffile; then
-    dpkg-maintscript-helper rm_conffile /etc/init.d/tmux-cleanup 1.4-6 -- "$@"
-fi
-
 #DEBHELPER#