[SPARK-2470] PEP8 fixes to rddsampler.py
[SPARK-2470] PEP8 fixes to cloudpickle.py
[SPARK-2470] PEP8 fixes to conf.py
[SPARK-2470] PEP8 fixes to context.py
[SPARK-2470] PEP8 fixes to daemon.py
[SPARK-2470] PEP8 fixes to java_gateway.py
[SPARK-2470] PEP8 fixes to resultiterable.py
[SPARK-2470] PEP8 fixes to __init__.py
[SPARK-2470] PEP8 fixes to join.py
[SPARK-2470] PEP8 fixes to mllib
[SPARK-2470] PEP8 fixes to serializers.py
[SPARK-2470] PEP8 fixes to shell.py
[SPARK-2470] PEP8 fixes to sql.py
[SPARK-2470] PEP8 fixes to worker.py
[SPARK-2470] PEP8 fixes to statcounter.py
[SPARK-2470] PEP8 fixes to storagelevel.py
[SPARK-2470] PEP8 fixes to tests.py