[SPARK-6773][Tests]Fix RAT checks still passed issue when download rat jar failed

[sisihj]

check -license will passed in next time when rat jar download failed.

Add 2 step to fix this:

1. Clean the rat.jar if download failed.
2. Add a check logic after run rat checking.

[AmplabJenkins]

Can one of the admins verify this patch?

[srowen]

This seems fine except that this message needs improvement. 'RAT exited abnormally' is probably fine.

[sisihj]

@srowen fixed according you comments, pls review.

[srowen]

Actually I also just noticed that this should be quoted as "$JAR", and above in the unzip command, to take care with paths containing spaces.

[srowen]

Looking again at the rest of the script, I don't see the point of if [[ ! -f "$rat_jar" ]]; then, since it's redundant with the check that follows. Both enclose the same code (excepting that final print statement, which doesn't matter). @ScrapCodes is that right? 21109fb

[ScrapCodes]

You are right, that check is just redundant ! + This PR LGTM given the fix that @srowen suggested is done.

[srowen]

ok to test

[SparkQA]

Test build #30033 has started for PR 5421 at commit 4958302.

[SparkQA]

Test build #30033 has finished for PR 5421 at commit 4958302.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.
• This patch does not change any dependencies.

[AmplabJenkins]

Test PASSed.
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https://amplab.cs.berkeley.edu/jenkins//job/SparkPullRequestBuilder/30033/
Test PASSed.