Master fails checks with new flake8 version

sumpy/point_calculus.py:236:17: E741 ambiguous variable name 'l'
sumpy/expansion/local.py:338:25: E741 ambiguous variable name 'l'
sumpy/expansion/local.py:356:21: E741 ambiguous variable name 'l'
sumpy/expansion/local.py:373:17: E741 ambiguous variable name 'l'
sumpy/expansion/local.py:388:17: E741 ambiguous variable name 'l'
sumpy/expansion/multipole.py:297:21: E741 ambiguous variable name 'l'
sumpy/expansion/multipole.py:315:21: E741 ambiguous variable name 'l'
sumpy/expansion/multipole.py:336:13: E741 ambiguous variable name 'l'
test/test_cse.py:257:9: E122 continuation line missing indentation or outdented
test/test_cse.py:260:9: E122 continuation line missing indentation or outdented

I can fix the last two. It seems silly to disallow l as a variable though.