Write proper error message when CBH can't find the configuration file.
Traceback (most recent call last):
File "./cumulus-bundle-handler", line 29, in <module>
import lib
File "/Users/sebastian/git/skymill/cumulus/cumulus-bundle-handler/lib/__init__.py", line 79, in <module>
'metadata', 'log-level').upper()
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/ConfigParser.py", line 607, in get
raise NoSectionError(section)
ConfigParser.NoSectionError: No section: 'metadata'
Write proper error message when CBH can't find the configuration file.