fix travis tests for py27 by try import collections.abc
fix travis tests for py27 by try import collections.abc

farseerfc/pelican,avaris/pelican,avaris/pelican,iKevinY/pelican,ingwinlu/pelican,talha131/pelican,ingwinlu/pelican,talha131/pelican,iKevinY/pelican,getpelican/pelican,farseerfc/pelican,getpelican/pelican