pgsql: Fix MSVC warning in compat_informix/rnull.pgc

Fix MSVC warning in compat_informix/rnull.pgc

Building the ecpg tests with MSVC, with warnings enabled, results in the
following warning:
src/interfaces/ecpg/test/compat_informix/rnull.pgc(19,1): warning C4305: 'initializing': truncation from 'double' to
'float'

The more obvious fix would be an 'f' suffix, but ecpg can't parse that.

Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Discussion: https://postgr.es/m/2180a97c-c026-1b6c-cec8-d6e499f97017@enterprisedb.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/483ac6476198c66696b725d49aa42290a9a94a95

Modified Files
--------------
src/interfaces/ecpg/test/compat_informix/rnull.pgc        | 2 +-
src/interfaces/ecpg/test/expected/compat_informix-rnull.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)