Switch python-classroom vagrant to Everything repo.

The Cloud tree does not contain python-classroom comps group.
And the Lab is not part of the Cloud Variant. So, we need to
use Everything install tree for Labs.

Signed-off-by: Mohan Boddu <mboddu@redhat.com>

fedora.conf

@@ -374,8 +374,8 @@ image_build = {
                     'distro': 'Fedora-22',
                     'disk_size': 40,
                     'arches': ['x86_64','i386'],
-                    'repo_from': 'Cloud',
-                    'install_tree_from': 'Cloud',
+                    'repo_from': 'Everything',
+                    'install_tree_from': 'Everything',
                     'subvariant': 'Python_Classroom'
                     'failable': ['*'],
                      }