[skara] RFR: 912: PR title correction logic can get stuck

[Magnus Ihse Bursie]

The PR title correct logic introduced with SKARA-572 can end up trying to correct the title forever. An observed case is where the JBS title ends with a trailing space. When trying to update the PR title to include this trailing space, it will be stripped by GitLab and no update will actually be done. This will then get retried again and again. 

The fix is to strip the JBS title before doing any comparisons.

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Commit messages:
 - 912: PR title correction logic can get stuck

Changes: https://git.openjdk.java.net/skara/pull/1050/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1050&range=00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-912
  Stats: 22 lines in 3 files changed: 17 ins; 0 del; 5 mod
  Patch: https://git.openjdk.java.net/skara/pull/1050.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1050/head:pull/1050

PR: https://git.openjdk.java.net/skara/pull/1050