[SPARK-6219] [Build] Check that Python code compiles

[nchammas]

This PR expands the Python lint checks so that they check for obvious compilation errors in our Python code.

For example:

$ ./dev/lint-python 
Python lint checks failed.
Compiling ./ec2/spark_ec2.py ...
  File "./ec2/spark_ec2.py", line 618
    return (master_nodes,, slave_nodes)
                         ^
SyntaxError: invalid syntax

./ec2/spark_ec2.py:618:25: E231 missing whitespace after ','
./ec2/spark_ec2.py:1117:101: E501 line too long (102 > 100 characters)

This PR also bumps up the version of pep8. It ignores new types of checks introduced by that version bump while fixing problems missed by the older version of pep8 we were using.

[SparkQA]

Test build #28375 has started for PR 4941 at commit 75e31d8.

• This patch merges cleanly.

[nchammas]

cc @JoshRosen @davies

[SparkQA]

Test build #28375 has finished for PR 4941 at commit 75e31d8.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[AmplabJenkins]

Test PASSed.
Refer to this link for build results (access rights to CI server needed):
https://amplab.cs.berkeley.edu/jenkins//job/SparkPullRequestBuilder/28375/
Test PASSed.

[JoshRosen]

LGTM. I'm going to let Jenkins retest this again and will merge once tests pass.

[JoshRosen]

Jenkins, retest this please.

[SparkQA]

Test build #28880 has started for PR 4941 at commit 75e31d8.

• This patch merges cleanly.

[davies]

LGTM

[SparkQA]

Test build #28880 has finished for PR 4941 at commit 75e31d8.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[AmplabJenkins]

Test PASSed.
Refer to this link for build results (access rights to CI server needed):
https://amplab.cs.berkeley.edu/jenkins//job/SparkPullRequestBuilder/28880/
Test PASSed.