Util: Print dbutil.go error in stderr

[michaeldiamant]

Addresses #4149 (comment) by switching from stdout to stderr.

[codecov]

Codecov Report

Merging #4712 (e20daa1) into master (0cb9a2e) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #4712      +/-   ##
==========================================
- Coverage   54.19%   54.17%   -0.02%     
==========================================
  Files         413      413              
  Lines       53408    53408              
==========================================
- Hits        28943    28935       -8     
- Misses      22056    22067      +11     
+ Partials     2409     2406       -3     

Impacted Files	Coverage Δ
util/db/dbutil.go	42.60% <0.00%> (ø)
network/wsPeer.go	66.50% <0.00%> (-1.95%)	⬇️
ledger/tracker.go	74.04% <0.00%> (-0.86%)	⬇️
ledger/acctupdates.go	68.56% <0.00%> (-0.75%)	⬇️
network/wsNetwork.go	65.34% <0.00%> (-0.19%)	⬇️
network/requestTracker.go	71.55% <0.00%> (+0.43%)	⬆️
ledger/testing/randomAccounts.go	57.23% <0.00%> (+0.61%)	⬆️
crypto/merkletrie/node.go	93.48% <0.00%> (+1.86%)	⬆️
crypto/merkletrie/trie.go	68.61% <0.00%> (+2.18%)	⬆️

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