toaster: Update deprecated manage.py command

toaster: Update deprecated manage.py command

syncdb is deprecated in favour of migrate in Django 1.7:
https://docs.djangoproject.com/en/1.8/releases/1.7/#schema-migrations

Update to the "migrate" command in Toaster's start script.

[YOCTO #8364]

Signed-off-by: Elliot Smith <elliot.smith@intel.com>
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: brian avery <avery.brian@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>