Depend on ifupdown in simple-init

Newer distros, such as debian jessie and ubuntu xenial, do not provide
ifupdown by default, but simple-init depends on it. Add it to the pile.

Change-Id: I6f4876863c67c65a82464d4e0593015cdc839c5c

elements/dib-init-system/dib-init-system

@@ -6,7 +6,9 @@ fi
 set -eu
 set -o pipefail
 
-if [[ -f /sbin/initctl ]]; then
+if [[ -f /usr/bin/systemctl ]]; then
+    echo "systemd"
+elif [[ -f /sbin/initctl ]]; then
     echo "upstart"
 elif [[ -f /etc/gentoo-release ]]; then
     if [[ "${GENTOO_PROFILE}" =~ systemd ]]; then
@@ -14,8 +16,6 @@ elif [[ -f /etc/gentoo-release ]]; then
     else
         echo "openrc"
     fi
-elif [[ -f /usr/bin/systemctl ]]; then
-    echo "systemd"
 elif [[ -f /sbin/init ]]; then
     if [[ -f /bin/systemd ]]; then
         echo "systemd"

elements/simple-init/package-installs.yaml

@@ -1,2 +1,3 @@
 isc-dhcp-client:
 net-tools:
+ifupdown:

elements/simple-init/pkg-map

@@ -4,7 +4,8 @@
       "isc-dhcp-client": "dhclient"
     },
     "debian": {
-      "isc-dhcp-client": "isc-dhcp-client"
+      "isc-dhcp-client": "isc-dhcp-client",
+      "ifupdown": "ifupdown"
     },
     "gentoo": {
       "isc-dhcp-client": "net-misc/dhcp",
@@ -13,6 +14,7 @@
     }
   },
   "default": {
-    "isc-dhcp-client": "isc-dhcp-client"
+    "isc-dhcp-client": "isc-dhcp-client",
+    "ifupdown": ""
   }
 }