p/fuel: Rebase, drop --depth=1 when cloning Fuel

p/fuel: Rebase, drop --depth=1 when cloning Fuel

`git clone --depth=1` does not preserve git history, so 3-way merge
is not possible.

There are 2 ways to fix this:
- (recurrent) rebase patches by adjusting patch context;
- (one-time, with a recurrent very small performance hit) preserve git
  history when cloning Fuel@OPNFV in salt.sh;

So, let's drop "--depth=1" and ensure `git am -3` will continue to work
on future patch context changes (where possbile).
While we're at it, also rebase our current patches.

Change-Id: Iacfb4daf90a170174405410ff9c988c4fcac79ca
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>