pgsql: Make VACUUM VERBOSE report the number of skipped frozen pages.

Make VACUUM VERBOSE report the number of skipped frozen pages.

Previously manual VACUUM did not report the number of skipped frozen
pages even when VERBOSE option is specified. But this information is
helpful to monitor the VACUUM activity, and also autovacuum reports that
number in the log file when the condition of log_autovacuum_min_duration
is met.

This commit changes VACUUM VERBOSE so that it reports the number
of frozen pages that it skips.

Author: Masahiko Sawada
Reviewed-by: Yugo Nagata and Jim Nasby

Discussion: http://postgr.es/m/CAD21AoDZQKCxo0L39Mrq08cONNkXQKXuh=2DP1Q8ebmt35SoaA@mail.gmail.com

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/70adf2fbe18f83f34b576ee83f42ea9d28375bf0

Modified Files
--------------
doc/src/sgml/ref/vacuum.sgml | 2 +-
src/backend/commands/vacuumlazy.c | 8 ++++++--
2 files changed, 7 insertions(+), 3 deletions(-)