pgsql: Use appendStringInfoString/Char et al where appropriate.

Use appendStringInfoString/Char et al where appropriate.

Patch by David Rowley. Backpatch to 9.5, as some of the calls were new in
9.5, and keeping the code in sync with master makes future backpatching
easier.

Branch
------
REL9_5_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/02ec4cd179099fc409288bb55c40fea308a51204

Modified Files
--------------
contrib/postgres_fdw/postgres_fdw.c | 2 +-
src/backend/access/rmgrdesc/gindesc.c | 4 ++--
src/backend/access/rmgrdesc/spgdesc.c | 10 +++++-----
src/backend/access/rmgrdesc/xactdesc.c | 2 +-
src/backend/access/transam/xlog.c | 4 ++--
src/backend/lib/pairingheap.c | 2 +-
src/backend/utils/adt/ruleutils.c | 2 +-
src/backend/utils/adt/xml.c | 6 +++---
src/bin/pg_basebackup/pg_basebackup.c | 2 +-
src/bin/pg_dump/pg_backup_archiver.c | 2 +-
src/bin/pg_dump/pg_dump.c | 6 +++---
src/bin/psql/describe.c | 8 ++++----
src/bin/scripts/clusterdb.c | 2 +-
src/bin/scripts/createdb.c | 4 ++--
src/bin/scripts/createuser.c | 2 +-
src/bin/scripts/reindexdb.c | 2 +-
src/bin/scripts/vacuumdb.c | 4 ++--
17 files changed, 32 insertions(+), 32 deletions(-)