DM-33394: Add debug log message if the cache transfer failed

[timj]

This was a useful message to have when debugging ResourcePath issues in lsst/resources#5

Checklist

• ran Jenkins
• added a release note for user-visible changes to doc/changes

[codecov]

Codecov Report

Merging #641 (b985217) into main (0e05172) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main     #641      +/-   ##
==========================================
- Coverage   83.78%   83.78%   -0.01%     
==========================================
  Files         239      239              
  Lines       30403    30404       +1     
  Branches     5049     5049              
==========================================
  Hits        25473    25473              
- Misses       3785     3786       +1     
  Partials     1145     1145              

Impacted Files	Coverage Δ
...thon/lsst/daf/butler/core/datastoreCacheManager.py	80.92% <0.00%> (-0.25%)	⬇️

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