Add make_app(config) to initialize_database

This is to fix the attribute error when running:

$ sudo rhaptos2repo-initdb develop.ini

INFO:rhaptos2.repo:logger set up on rhaptos2.repo as <logging.Logger object at 0x17e57d0>
Traceback (most recent call last):
  File "/usr/local/bin/rhaptos2repo-initdb", line 9, in <module>
    load_entry_point('rhaptos2.repo==0.1', 'console_scripts', 'rhaptos2repo-initdb')()
  File "/usr/local/lib/python2.7/dist-packages/rhaptos2.repo-0.1-py2.7.egg/rhaptos2/repo/run.py", line 57, in initialize_database
    from rhaptos2.repo.backend import initdb
  File "/usr/local/lib/python2.7/dist-packages/rhaptos2.repo-0.1-py2.7.egg/rhaptos2/repo/backend.py", line 14, in <module>
    from .model import connect_now, initdb
  File "/usr/local/lib/python2.7/dist-packages/rhaptos2.repo-0.1-py2.7.egg/rhaptos2/repo/model.py", line 114, in <module>
    db_engine = connect_now(get_app().config)
AttributeError: 'NoneType' object has no attribute 'config'