initramfs: initialize volatile.img partition table also in TemplateVM

While there is no additional snapshot device, swap partition is still
used.

Fixes QubesOS/qubes-issues#1308

dracut/full-dmroot/qubes_cow_setup.sh

@@ -83,6 +83,15 @@ EOF
     log_end
 else
     log_begin "Qubes: Doing R/W setup for TemplateVM..."
+    while ! [ -e /dev/xvdc ]; do sleep 0.1; done
+    sfdisk -q --unit S /dev/xvdc >/dev/null <<EOF
+1,$SWAP_SIZE,S
+EOF
+    if [ $? -ne 0 ]; then
+        die "Qubes: failed to setup partitions on volatile device"
+    fi
+    while ! [ -e /dev/xvdc1 ]; do sleep 0.1; done
+    mkswap /dev/xvdc1
     echo "0 `cat /sys/block/xvda/size` linear /dev/xvda 0" | \
         dmsetup --noudevsync create dmroot || die "Qubes: FATAL: cannot create dmroot!"
     log_end

dracut/simple/init.sh

@@ -44,6 +44,15 @@ EOF
     echo Qubes: done.
 else
     echo "Qubes: Doing R/W setup for TemplateVM..."
+    while ! [ -e /dev/xvdc ]; do sleep 0.1; done
+    sfdisk -q --unit S /dev/xvdc >/dev/null <<EOF
+1,$SWAP_SIZE,S
+EOF
+    if [ $? -ne 0 ]; then
+        die "Qubes: failed to setup partitions on volatile device"
+    fi
+    while ! [ -e /dev/xvdc1 ]; do sleep 0.1; done
+    mkswap /dev/xvdc1
     echo "0 `cat /sys/block/xvda/size` linear /dev/xvda 0" | \
         dmsetup create dmroot || { echo "Qubes: FATAL: cannot create dmroot!"; exit 1; }
     echo Qubes: done.