Fix logging setup for Python 3.4

The logging.getLevelName is supposed to be used to get string
representation from integer code, not vice versa. It is possible to get
int code from the string using this function in Python 2, but not in
Python 3.4, where for example getLevelName('DEBUG') will return
'Level DEBUG' instead of 10.
Only in Python2.6, Logger.setLevel doesn't do automatic
conversion, and thus requires call to getLevelName.

Closes-bug: #1322701
Change-Id: I4500681e842f0c1799931407fa66c660bdaf2d41
Merge "Fix logging setup for Python 3.4"