Unify the strategy of tolerating tail corruption when Version == V2.

[LykxSassinator]

Supplemented bugfix for #249 , to unify the strategy on whether tolerating the tail corruption when version == V2.

Signed-off-by: Lucasliang nkcs_lykx@hotmail.com

[LykxSassinator]

/cc @tabokie thanks for reviewing.

[codecov]

Codecov Report

Merging #255 (6717f8f) into master (c3a6156) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #255      +/-   ##
==========================================
- Coverage   97.24%   97.22%   -0.02%     
==========================================
  Files          30       30              
  Lines       10951    10989      +38     
==========================================
+ Hits        10649    10684      +35     
- Misses        302      305       +3     

Impacted Files	Coverage Δ
src/file_pipe_log/format.rs	98.95% <100.00%> (+0.02%)	⬆️
src/file_pipe_log/log_file.rs	99.58% <100.00%> (+0.02%)	⬆️
src/file_pipe_log/pipe_builder.rs	96.25% <100.00%> (+0.01%)	⬆️
tests/failpoints/test_engine.rs	99.84% <100.00%> (+<0.01%)	⬆️
src/consistency.rs	91.11% <0.00%> (-2.23%)	⬇️
src/env/default.rs	92.39% <0.00%> (-0.55%)	⬇️
src/log_batch.rs	97.57% <0.00%> (-0.10%)	⬇️

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[tabokie]

Closing this, I'll fix it in #244

[tabokie]

Actually, this is not possible anymore with file recycle. Because file_size is already larger than header_size even before the header is written.