pgsql: Fix incorrect initialization of ProcGlobal->startupBufferPinWait

Fix incorrect initialization of ProcGlobal->startupBufferPinWaitBufId.

It was initialized in the wrong place and to the wrong value.  With bad
luck this could result in incorrect query-cancellation failures in hot
standby sessions, should a HS backend be holding pin on buffer number 1
while trying to acquire a lock.

Branch
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REL9_1_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/0dd6a09e3d127e728b9f43cfaf19e5351f60a096

Modified Files
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src/backend/storage/buffer/bufmgr.c |    3 ++-
src/backend/storage/lmgr/proc.c     |   10 ++++------
src/include/storage/proc.h          |    2 +-
3 files changed, 7 insertions(+), 8 deletions(-)