Handle automatic dry_runs in GandiModule.call.

Passing a dry_run=True param to GandiModule.call will now automatically call
the dry_run if a call fail, to have more imformations on why it failed, and
will display it.
Use dry_run=True attribute for vhost.create.
Merge branch 'stable'
Merge branch 'stable'
Merge branch 'stable'
Revert "we are currently basing kernel list on image.list()"

This reverts commit 3f3143b0f517abc0c8019a104620a2300948deac.
core: enhance kernel list

we are currently basing kernel list on image.list()
some issues:
1. the list contains duplicates since we extract each kernel from all
   images
2. if the kernel is not included on an image, we will not be able to set
   it
   example:
   for grub, we currently don't have any image based on grub, so I had
   to insert an empty image with the grub kernel in order to make it
   work
3. we should check if the datacenter has the needed kernel before
setting it

this patch proposes to base the kernel list on the first datacenter
since for now, we may consider that all datacenter have the same
kernels.
This solution is not ideal but it avoids to insert an empty image with
the grub kernel which could confuse users.

A second patch should check the kernel depending on the disk's
datacenter.

Signed-off-by: William Dauchy <william@gandi.net>
iaas: be more verbose when logging step infos

when deleting several VM the log was describing all operation one
after another without showing which VM concerned.
I thought it was a good this to add such info.
I expanded it to all `echo` for the IAAS module.

Reviewed-by: sayoun <sayoun@gandi.net>
Signed-off-by: William Dauchy <william@gandi.net>
cli: cleaning trailing whitespaces

Signed-off-by: William Dauchy <william@gandi.net>
Merge branch 'stable'
Merge branch 'stable'
Merge branch 'stable'
'gandi vm delete' command should check for all valid resources
Apply PEP8
Fix typo in domain create description.
base: support adding modules using GANDICLI_PATH

we currently support adding additionnal commands using GANDICLI_PATH
this patch adds support for loading additionnal modules

Signed-off-by: William Dauchy <william@gandi.net>
Handle new connection error since we use request as xmlrpc transport
When an API call fail, we can call again using dry-run to get explicit errors.

Activate dry-run flag to vhost creation.
Refactor code of vm delete command to accept all valid resources, names or ID
Fixes various typo in documentation
Some PEP8