Tim - redirect back to base image show page after build & push actions

After creating new target or provider image we want go back to
base image show page. If we want to avoid overriding whole controller action
we have to change default respond behavior - this is done in custom
RedirResponder which is used only for UI create/destroy actions for Tim.

This responder only sets any error into flash message and redirect to specified
URL.
Removed logging of exception backtrace if architecture can't be found

This backtrace was just informative, but it can be confusing to print
this excpetion in log because this happens for all imported images.
Temporary fix for duplicit error messages on image import page

This is hotfix for https://github.com/aeolus-incubator/tim/issues/69 issue.
Updated displaying of build/push/delete buttons for image

Proper button is displayed based on current status of target/provider
image. If build or push is in progress, no button is displayed, only status
label if progress.
Added new Tim migrations
Fixed const definitions in decorators

Wrong scope (global) was used for defined constants, to avoid this
full path is used in decorators.
Fixed displaying of status on deployable show page
Fixed setting of target image's target if provider_type is nil
Fixed passing of provider parameter to imagefactory

Imagefactory requires additional parameters when pushing
openstack image. it's possible that similar problem will
be for other provider types (rhevm, vsphere).
Added openstack specific credential fields

These fields are required by imagefactory
Fixed checking of last build

There can be multiple builds for an image version,
in such case grab first *completed*.
Fixed forgotten call to iwhd
Bumped Tim version in Gemfile.lock
Fixed creation of new image

Removed creation of template from url/uploaded file from base image model.
Created DownloadService for downloading files from url.
Replaced import_from_xml by DownloadService in existing code

There is still an obsolete import_xml_from_url method in
app/util/deployable_xml.rb which is apparently used only in tests.
This will be removed in separate patch because it fix is not
straightforward.
Bumped deltacloud-client version to 1.0.4

We had quite old 0.5.0 version of deltacloud-client in Gemfile.lock.
This version doesn't play nicely with openstack provider - it's not
possible to add openstack provider account because x-deltacloud-provider
header is not sent properly. There is also newer version 1.0.5 now, but
bumping to 1.0.4 which I know is in Fedora.
Merge pull request #308 from jprovaznik/tim-integration_fixes_rev2

Tim integration fixes rev2