pgsql: Fix initdb's handling of min_wal_size and max_wal_size.

Fix initdb's handling of min_wal_size and max_wal_size.

In commit 3e51b278d, I misinterpreted the coding in setup_config()
as setting min_wal_size and max_wal_size to compile-time-constant
values. But it's not: there's a hidden dependency on --wal-segsize.
Therefore leaving these variables commented out is the wrong thing.
Per report from Andres Freund.

Discussion: https://postgr.es/m/20230322200751.jvfvsuuhd3hgm6vv@awork3.anarazel.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/b48af6d174bb39bd688d52795aef2b9c10dd6e8c

Modified Files
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src/bin/initdb/initdb.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)