pgsql: Rename I/O timing statistics columns to blk_read_time and blk_wr

Rename I/O timing statistics columns to blk_read_time and blk_write_time.

This seems more consistent with the pre-existing choices for names of
other statistics columns. Rename assorted internal identifiers to match.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/1dd89eadcd2648d7ca0baed3c7af16a04eb1aa26

Modified Files
--------------
.../pg_stat_statements--1.0--1.1.sql | 4 +-
.../pg_stat_statements/pg_stat_statements--1.1.sql | 4 +-
contrib/pg_stat_statements/pg_stat_statements.c | 30 ++++++++++----------
doc/src/sgml/monitoring.sgml | 6 +--
doc/src/sgml/pgstatstatements.sgml | 4 +-
src/backend/catalog/system_views.sql | 4 +-
src/backend/commands/explain.c | 20 ++++++------
src/backend/executor/instrument.c | 6 ++-
src/backend/postmaster/pgstat.c | 28 +++++++++---------
src/backend/storage/buffer/bufmgr.c | 4 +-
src/backend/utils/adt/pgstatfuncs.c | 12 ++++----
src/include/catalog/catversion.h | 2 +-
src/include/catalog/pg_proc.h | 4 +-
src/include/executor/instrument.h | 12 ++++----
src/include/pgstat.h | 16 +++++-----
src/test/regress/expected/rules.out | 2 +-
16 files changed, 79 insertions(+), 79 deletions(-)