pgsql: Fix hard-coded relkind constants in assorted src/bin files.

Fix hard-coded relkind constants in assorted src/bin files.

Although it's reasonable to expect that most of these constants will
never change, that does not make it good programming style to hard-code
the value rather than using the RELKIND_FOO macros.

Discussion: https://postgr.es/m/11145.1488931324@sss.pgh.pa.us

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/fcd778eb703c154c0fbba249e17c21b7ae4de19b

Modified Files
--------------
src/bin/initdb/initdb.c | 17 ++++++++++++----
src/bin/pg_dump/pg_dump_sort.c | 14 +++++++------
src/bin/pg_upgrade/info.c | 4 +++-
src/bin/pg_upgrade/pg_upgrade.c | 11 ++++++++--
src/bin/pg_upgrade/version.c | 7 ++++++-
src/bin/psql/command.c | 5 +++--
src/bin/psql/tab-complete.c | 45 ++++++++++++++++++++++++++++-------------
src/bin/scripts/vacuumdb.c | 10 +++++++--
8 files changed, 81 insertions(+), 32 deletions(-)