pgsql: Prevent possible compiler warnings.

Prevent possible compiler warnings.

Back-patch commit a3e8486dffc413506b14eae9dc5d423f6ae8324a into the 9.0
branch.  This is the only warning I'm seeing in the live branches with
gcc 4.4.7 (other than the known "unused variable 'yyg'" flex lossage),
which makes it just annoying enough to want to clean up.

Branch
------
REL9_0_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/a74f50a3f627ac2ef73c77dc1b6ea67d0d44da50

Modified Files
--------------
src/backend/utils/adt/dbsize.c |    3 +++
1 file changed, 3 insertions(+)