pgsql: Fix confusion between "size" and "AnonymousShmemSize".

Fix confusion between "size" and "AnonymousShmemSize".

Noted by Andres Freund. Also improve a couple of comments.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/42e2ce6ae3e931953135a55b173a5ec4c54506c4

Modified Files
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src/backend/port/sysv_shmem.c | 12 +++++++-----
1 files changed, 7 insertions(+), 5 deletions(-)