pgsql: Use 0-based numbering in comments about backup blocks.

Use 0-based numbering in comments about backup blocks.

The macros and functions that work with backup blocks in the redo function
use 0-based numbering, so let's use that consistently in the function that
generates the records too. Makes it so much easier to compare the
generation and replay functions.

Backpatch to 9.0, where we switched from 1-based to 0-based numbering.

Branch
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REL9_3_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/e0c04b7c3833c3874bf8ca91eb3a8ef45ac00ae4

Modified Files
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src/backend/access/nbtree/nbtinsert.c |   10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)