[BUILD] Closing stale PRs

[srowen]

Closes#15303
Closes#15078
Closes#15080
Closes#15135
Closes#14565
Closes#12355
Closes#15404

[SparkQA]

Test build #66817 has finished for PR 15451 at commit 4d40636.

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

[rxin]

Merging in master.

[rxin]

Actually I'm getting error when merging. Not sure why.

[vanzin]

Let me try...

[vanzin]

Done. I had to temporarily add --allow-empty to the git commit command in ./dev/merge_spark_pr.py. Perhaps we should fix the script to always add that option (or have some command line switch for it).

[srowen]

Yes you have to add --allow-empty temporarily. I hadn't added it to the script because usually we don't want to allow an empty commit. Yes if this becomes pretty regular, probably worth some kind of check and prompt during the script that would allow this to proceed without temporarily changing the script.