[fix] duckduckgo_definition issues reported by 'manage.sh test'

Fix this error while travis build::

  /home/travis/build/asciimoo/searx/searx/engines/duckduckgo_definitions.py:21:44: E225 missing whitespace around operator

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/engines/duckduckgo_definitions.py

@@ -18,7 +18,7 @@ from searx.engines.duckduckgo import _fetch_supported_languages, supported_langu
 from searx.url_utils import urlencode
 from searx.utils import html_to_text, match_language
 
-logger = logging.getLogger('searx.engines.'+ __name__)
+logger = logging.getLogger('searx.engines.' + __name__)
 
 url = 'https://api.duckduckgo.com/'\
     + '?{query}&format=json&pretty=0&no_redirect=1&d=1'