pgsql: Avoid inconsistent type declaration

Avoid inconsistent type declaration

Clang 3.3 correctly complains that a variable of type enum
MultiXactStatus cannot hold a value of -1, which makes sense.  Change
the declared type of the variable to int instead, and apply casting as
necessary to avoid the warning.

Per notice from Andres Freund

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/4ca50e071024421e3b75bf7e48fda08141360636

Modified Files
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src/backend/access/heap/heapam.c |   11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)