create-image: add Vagrant support

With this patch create-image.sh gains the ability to
generate a .box Vagrant file in qcow2/libvirt format.
create-image: ensure loop is loaded

loop kernel module is a required. In some rare cases, the module can
be unloaded.
create-image: getopts parameters handling

This patch introduces the use of getopts to handles the parameters:

 -d directory of the eDeploy role
 -n name of the image
 -c optional: configuration file
 -v optional: enable the Vagrant support
create-image: -V $provider

-v is in general used to enable verbose mode. So let's use -V instead.

-V now accept a Vagrant provider.
restore the DIR and IMG parameter

those parameters are not optional argument.
create-image: avoid hardcoded variables
create-image: information message regarding vagrant

show up a nice message once the Vagrant box is ready
create-image: source CFG the old way
Merge pull request #60 from enovance/vagrant

Vagrant