pgsql: Suppress compiler warnings in dshash.c.

Suppress compiler warnings in dshash.c.

Some compilers complain, not unreasonably, about left-shifting an
int32 "1" and then assigning the result to an int64. In practice
I sure hope that this data structure never gets large enough that
an overflow would actually occur; but let's cast the constant to
the right type to avoid the hazard.

In passing, fix a typo in dshash.h.

Amit Kapila, adjusted as per comment from Thomas Munro.

Discussion: https://postgr.es/m/CAA4eK1+5vfVMYtjK_NX8O3-42yM3o80qdqWnQzGquPrbq6mb+A@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/4faa1dc2eb02ba67303110e025d44abb40b12725

Modified Files
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src/backend/lib/dshash.c | 8 ++++----
src/include/lib/dshash.h | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)