pgsql: Switch back sslcompression to be a normal input field in libpq

Switch back sslcompression to be a normal input field in libpq

Per buildfarm member crake, any servers including a postgres_fdw server
with this option set would fail to do a pg_upgrade properly as the
option got hidden in f9264d1 by becoming a debug option, making the
restore of the FDW server fail.

This changes back the option in libpq to be visible, but still inactive
to fix this upgrade issue.

Discussion: https://postgr.es/m/YEbq15JKJwIX+S6m@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/096bbf7c934a4288c9e48a6ac8e91d8753ac1ccd

Modified Files
--------------
contrib/postgres_fdw/expected/postgres_fdw.out | 3 ++-
contrib/postgres_fdw/sql/postgres_fdw.sql | 1 +
src/interfaces/libpq/fe-connect.c | 2 +-
3 files changed, 4 insertions(+), 2 deletions(-)