pgsql: Fix bogus handling of bad strategy number in GIST consistent() f

Fix bogus handling of bad strategy number in GIST consistent() functions.

Make sure we throw an error instead of silently doing the wrong thing when
fed a strategy number we don't recognize. Also, in the places that did
already throw an error, spell the error message in a way more consistent
with our message style guidelines.

Per report from Paul Jones. Although this is a bug, it won't occur unless
a superuser tries to do something he shouldn't, so it doesn't seem worth
back-patching.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/4dfb065b3ab662dcc96d07ee7fc9dadf6975a0cb

Modified Files
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src/backend/access/gist/gistproc.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)