pgsql: Clean up more unused variables in perl code

Clean up more unused variables in perl code

This is a continuation of 0c1aca461481, with some cleanup in:
- msvc_gendef.pl
- pgindent
- 005_negotiate_encryption.pl, as of an oversight of d39a49c1e459 that
has removed %params in test_matrix(), making also $server_config
useless.

Author: Dagfinn Ilmari Mannsåker
Discussion: https://postgr.es/m/87wmm4dkci.fsf@wibble.ilmari.org

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/dd569214aa7d057a9676c49ddbf2da74ad9924e3

Modified Files
--------------
src/interfaces/libpq/t/005_negotiate_encryption.pl | 24 ++++++----------------
src/tools/msvc_gendef.pl                           |  2 --
src/tools/pgindent/pgindent                        |  3 +--
3 files changed, 7 insertions(+), 22 deletions(-)