Merge #10714: Avoid printing incorrect block indexing time due to uninitialized variable

Summary:
959dd8781 Avoid printing incorrect block indexing time due to uninitialized variable (practicalswift)

Tree-SHA512: a76e43c3ffa734ed5c7eadf363f345f268aa0e6ce775aba8f856fe3bbc82f240dc7c734c5ca3ac500a12eb41fae00623413e79f484d5acf809b6e400851d771d

Backport of Core PR10714
https://github.com/bitcoin/bitcoin/pull/10714/files

Test Plan: make check

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D3209