pgsql: Further minor improvement in generic_xlog.c: always say REGBUF_S

Further minor improvement in generic_xlog.c: always say REGBUF_STANDARD.

Since we're requiring pages handled by generic_xlog.c to be standard
format, specify REGBUF_STANDARD when doing a full-page image, so that
xloginsert.c can compress out the "hole" between pd_lower and pd_upper.
Given the current API in which this path will be taken only for a newly
initialized page, the hole is likely to be particularly large in such
cases, so that this oversight could easily be performance-significant.
I don't notice any particular change in the runtime of contrib/bloom's
regression test, though.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/660d5fb856c61df2de2cedb26249404ffc58cb89

Modified Files
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src/backend/access/transam/generic_xlog.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)