Update xrootd to 4.8.5

[mrodozov]

Resolves: #4617

[mrodozov]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/32456/console

[cmsbuild]

A new Pull Request was created by @mrodozov (Mircho Rodozov) for branch IB/CMSSW_10_5_X/gcc700.

@cmsbuild, @smuzaffar, @gudrutis, @mrodozov can you please review it and eventually sign? Thanks.
You can sign-off by replying to this message having '+1' in the first line of your reply.
You can reject by replying to this message having '-1' in the first line of your reply.

[cmsbuild]

+1
Tested at: 2dc3452
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-4621/32456/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-4621/32456/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 33
• DQMHistoTests: Total histograms compared: 3153717
• DQMHistoTests: Total failures: 2
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3153511
• DQMHistoTests: Total skipped: 204
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 32 files compared)
• Checked 137 log files, 14 edm output root files, 33 DQM output files

[smuzaffar]

+externals

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next IB/CMSSW_10_5_X/gcc700 IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @davidlange6, @slava77, @smuzaffar, @fabiocos (and backports should be raised in the release meeting by the corresponding L2)