Build a small automate model using factory girl

This PR builds a small automate model with the hierarchy
 DOMAINS
      NAMESPACES
          CLASS
              INSTANCES
              METHODS
e.g.
FactoryGirl.create(:miq_ae_domain, :with_small_model, :with_instances, :name => 'FRED')
FactoryGirl.create(:miq_ae_domain, :with_small_model, :with_instances,
:with_method, :name => 'BARNEY')
git ls-remote expects stdin to be open so don't close it.

Don't close stdin in the launcher/daemonized script, which is the parent of all processes during the nightly build including the process that runs git ls-remote.

```
$ git ls-remote upstream master
0951f72dc29b7bda21f4e253eac2ab38ef03a60a  refs/heads/master

$ git ls-remote upstream master 0<&-
$
```

See also: http://git.661346.n2.nabble.com/Bug-Failure-if-stdin-is-closed-td7591627.html
Merge pull request #217 from jrafanie/fix_missing_git_sha1_for_realz

git ls-remote expects stdin to be open so don't close it.
Merge pull request #193 from mkanoor/factory_automate_model

Build a small automate model using factory girl
Set default_value_for PxeServer#customization_directory

https://bugzilla.redhat.com/show_bug.cgi?id=1081006
Migrate any PXE server #customization_directory that is nil to ""

https://bugzilla.redhat.com/show_bug.cgi?id=1081006