RFR: SKARA-1333: Sponsor label only removed if PR is actually sponsored [v2]

[Guoxiong Li]

> Hi all,
> 
> If an author types `/integrate` command, the `sponsor` label is added. When the author becomes the committer and types the command `/integrate` again, the `sponsor` label doesn't been removed. It is good to remove the label `sponsor`, too, just like the labels `rfr` and `ready`. This patch fixes it and adds a test case.
> 
> Thanks for taking the time to review.
> 
> Best Regards,
> -- Guoxiong

Guoxiong Li has updated the pull request incrementally with one additional commit since the last revision:

  Fix comments.

-------------

Changes:
  - all: https://git.openjdk.java.net/skara/pull/1282/files
  - new: https://git.openjdk.java.net/skara/pull/1282/files/7b578dda..a9667998

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=1282&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=1282&range=00-01

  Stats: 3 lines in 2 files changed: 0 ins; 1 del; 2 mod
  Patch: https://git.openjdk.java.net/skara/pull/1282.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1282/head:pull/1282

PR: https://git.openjdk.java.net/skara/pull/1282