add preinst script

Older versions of our daemona do not restart with HUP, so we
need to do a stop/start.

Makefile

@@ -43,6 +43,7 @@ ${DEB} deb:
 	install -m 0644 debian/conffiles dest/DEBIAN
 	install -m 0755 debian/config dest/DEBIAN
 	install -m 0644 debian/templates dest/DEBIAN
+	install -m 0755 debian/preinst dest/DEBIAN
 	install -m 0755 debian/postinst dest/DEBIAN
 	install -m 0755 debian/prerm dest/DEBIAN
 	install -m 0755 debian/postrm dest/DEBIAN

debian/preinst

@@ -0,0 +1,31 @@
+#!/bin/sh
+
+set -e
+
+DAEMONS="pveproxy spiceproxy pvestatd pvedaemon"
+
+case "$1" in
+    install|upgrade)
+	old_version=$2
+	if [ ! -e /proxmox_install_mode ]; then  
+	    if dpkg --compare-versions "$old_version" lt '3.3-9' ; then
+		echo "Detected old pve-manager version - using stop/start to restart daemons"
+		for i in ${DAEMONS}; do
+		    if [ -e "/usr/bin/$i" ]; then
+			/usr/bin/$i stop
+		    fi
+		done
+	    fi
+	fi
+    ;;
+
+    abort-upgrade)
+    ;;
+
+    *)
+        echo "preinst called with unknown argument \`$1'" >&2
+        exit 1
+    ;;
+esac
+
+exit 0