Fix flake8 errors

Author: amanda11

st2common/st2common/constants/error_messages.py

@@ -34,6 +34,7 @@
 "st2 run packs.setup_virtualenv packs=%(pack)s python3=false"
 '''
 
-PYTHON2_DEPRECATION = 'DEPRECATION WARNING. Support for python 2 will be removed in future StackStorm ' \
-'release(s). Please ensure that all packs used are python 3 compatible. Python 3 will already be used ' \
-'if you upgrade to a newer OS release.'
+PYTHON2_DEPRECATION = 'DEPRECATION WARNING. Support for python 2 will be removed in future ' \
+                      'StackStorm release(s). Please ensure that all packs used are python ' \
+                      '3 compatible. Python 3 will already be used if you upgrade to a newer ' \
+                      ' OS release.'

st2common/st2common/service_setup.py

@@ -191,7 +191,6 @@ def setup(service, config, setup_db=True, register_mq_exchanges=True,
         LOG.warning(PYTHON2_DEPRECATION)
 
 
-
 def teardown():
     """
     Common teardown function.