patch-id: ignore newline at end of file in diff_flush_patch_id()

[git] / t / t4013 / diff.diff-tree_-R_--stat_--compact-summary_initial_mode

$ git diff-tree -R --stat --compact-summary initial mode
 file0 (mode -x) | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
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