pgsql: A minor simplification for List manipulation

A minor simplification for List manipulation

Fix one place that was using lfirst(list_head(list)) by using linitial(list)
instead.  They are equivalent but the latter is simpler.  We did the same in
9d299a49.

Author: Richard Guo <guofenglinux@gmail.com>
Discussion:
https://www.postgresql.org/message-id/flat/CAMbWs49dJnpezDQDDxCPKq7+=_3NyqLqGqnhqCjd+dYe4MS15w@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/6d56c501a75fe0fd0b7104b3efee55e1cea8e80a

Modified Files
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src/backend/rewrite/rewriteSearchCycle.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)