web_framework: Split initialization into two parts

A simple Django configuration does not need to create the database whereas DB
migration requires creating the database.

In some operations such as listing dependencies, we can skip running the second
part and so writing to database will no longer be necessary during such
operations.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/__main__.py

@@ -132,6 +132,7 @@ def main():
     log.init()
 
     web_framework.init()
+    web_framework.post_init()
 
     logger.info('FreedomBox Service (Plinth) version - %s', __version__)
     for config_file in cfg.config_files:

plinth/web_framework.py

@@ -53,6 +53,9 @@ def init():
     logger.debug('Configured Django with applications - %s',
                  settings.INSTALLED_APPS)
 
+
+def post_init():
+    """Perform operations after completing init of other modules."""
     logger.debug('Creating or adding new tables to data file')
     django.core.management.call_command('migrate', '--fake-initial',
                                         interactive=False, verbosity=0)