pgsql: Avoid possible crash in contrib/bloom's blendscan().

Avoid possible crash in contrib/bloom's blendscan().

It's possible to begin and end an indexscan without ever calling
amrescan. contrib/bloom, unlike every other index AM, allocated
its "scan->opaque" storage at amrescan time, and thus would crash
in amendscan if amrescan hadn't been called. We could fix this
by putting in a null-pointer check in blendscan, but I see no very
good reason why contrib/bloom should march to its own drummer in
this respect. Let's move that initialization to blbeginscan
instead. Per report from Jeff Janes.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/e13ac5586c49c77f301329b79bd7e8f489d0e66f

Modified Files
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contrib/bloom/blscan.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)