Retry on ctags tagLine == null. Adjust ctags logging.

[idodeclare]

Hello,

Please consider for integration this patch to eject a problematic ctags instance from the pool and to retry for the affected file.

Log messages are adjusted slightly for clarity.

Thank you.

[coveralls]

Pull Request Test Coverage Report for Build 3743

• 7 of 14 (50.0%) changed or added relevant lines in 1 file are covered.
• 5 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.01%) to 73.425%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
opengrok-indexer/src/main/java/org/opengrok/indexer/analysis/Ctags.java	7	14	50.0%

Files with Coverage Reduction	New Missed Lines	%
opengrok-indexer/src/main/java/org/opengrok/indexer/analysis/Ctags.java	5	82.58%

Totals
Change from base Build 3733:	-0.01%
Covered Lines:	32848
Relevant Lines:	44737

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💛 - Coveralls

[vladak]

Looks good, thanks !