[FIX] *: clean useless content in manifests

Make sure the linting test added in community do not fail.

closes odoo/design-themes#668

X-original-commit: f78f8df161
Signed-off-by: Romain Derie (rde) <rde@odoo.com>
Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>

theme_common/__manifest__.py

@@ -11,6 +11,5 @@
         'views/old_snippets/s_page_header.xml',
         'views/old_snippets/s_three_columns_circle.xml',
     ],
-    'application': False,
     'license': 'LGPL-3',
 }