postgresql13-13.1-5.3.15

- bsc#1178961: %ghost the symlinks to pg_config and ecpg.
- boo#1179765: BuildRequire libpq5 and libecpg6 when not building
  them to avoid dangling symlinks in the devel package.

- Upgrade to version 13.1:
  * CVE-2020-25695, bsc#1178666: Block DECLARE CURSOR ... WITH HOLD
    and firing of deferred triggers within index expressions and
    materialized view queries.
  * CVE-2020-25694, bsc#1178667:
    a) Fix usage of complex connection-string parameters in pg_dump,
    pg_restore, clusterdb, reindexdb, and vacuumdb.
    b) When psql's \connect command re-uses connection parameters,
    ensure that all non-overridden parameters from a previous
    connection string are re-used.
  * CVE-2020-25696, bsc#1178668: Prevent psql's \gset command from
    modifying specially-treated variables.
  * Fix recently-added timetz test case so it works when the USA
    is not observing daylight savings time.
    (obsoletes postgresql-timetz.patch)
  * https://www.postgresql.org/about/news/2111/
  * https://www.postgresql.org/docs/13/release-13-1.html

- Fix a DST problem in the test suite: postgresql-timetz.patch
  https://postgr.es/m/16689-57701daa23b377bf@postgresql.org

- Initial packaging of PostgreSQL 13:
  * https://www.postgresql.org/about/news/2077/
  * https://www.postgresql.org/docs/13/release-13.html