F19 GRUB configuration file

In the 51-grub hook, after the GRUB installation, the script will look
for a GRUB configuration file and in case it's not present one will
be generated using the grub-mkconfig command. The reason why it have
to be done is because the new Fedora 19 cloud images is using extlinux
by default.

Change-Id: I80b15b3122698d98ac4d47dc06faf5909a90ab00

elements/vm/finalise.d/51-grub

@@ -35,6 +35,17 @@ if [ -f "/boot/grub/grub.cfg" ] ; then
 elif [ -f "/boot/grub2/grub.cfg" ] ; then
   GRUB_CFG=/boot/grub2/grub.cfg
 fi
+
+# If GRUB configuration file does not exist, generate one
+if [ ! $GRUB_CFG ]; then
+  if [ -d /boot/grub2 ]; then
+    GRUB_CFG=/boot/grub2/grub.cfg
+  elif [ -d /boot/grub ]; then
+    GRUB_CFG=/boot/grub/grub.cfg
+  fi
+  grub2-mkconfig -o $GRUB_CFG
+fi;
+
 DIST=`lsb_release -is`
 [ -n "$DIST" ]
 RELEASE=`lsb_release -cs`