pgsql: Fix bug introduced by the recent patch to check that the checkpo

Fix bug introduced by the recent patch to check that the checkpoint redo
location read from backup label file can be found: wasShutdown was set
incorrectly when a backup label file was found.

Jeff Davis, with a little tweaking by me.

Branch
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REL9_0_STABLE

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=9dba66c0e5248ad70f0a45b1b39ece6b1f549d53

Modified Files
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src/backend/access/transam/xlog.c |    4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)