Fix veryfirstboot script

The veryfirstboot script was running far more often than just the first boot.
We now write the stamp file earlier, in case any likely-to-fail operations do
fail.

Signed-off-by: Mike McClurg <mike.mcclurg@citrix.com>
make clean removes lib/templates.ml

Without this step, no changes to any of the install templates will be
recognised, causing hours of confusion.

Signed-off-by: Mike McClurg <mike.mcclurg@citrix.com>
Merge pull request #7 from mcclurmc/fix-veryfirstboot

Fix veryfirstboot template so that it only runs on the very first boot