Set log level to default value

Instead of setting the log level hard coded to INFO just let the used
logger module decide which level is the default. Otherwise a usage
of this module will change the log level globally to INFO which is not
the default for the python logger module (see
http://hg.python.org/cpython/file/2.7/Lib/logging/__init__.py#l1490)

Change-Id: I75a0517564e6829dfc1451c77da888548ad2219c
Closes-bug: 1320841