pgsql: Allow to lock views.

Allow to lock views.

Now all tables used in view definitions can be recursively locked by a
LOCK command.

Author: Yugo Nagata
Reviewed by Robert Haas, Thomas Munro and me.

Discussion: https://postgr.es/m/20171011183629.eb2817b3.nagata%40sraoss.co.jp

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/34c20de4d0b0ea8f96d0c518724d876c7b984cf5

Modified Files
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doc/src/sgml/ref/lock.sgml         |   5 ++
src/backend/commands/lockcmds.c    | 139 +++++++++++++++++++++++++++++++++----
src/test/regress/expected/lock.out | 100 +++++++++++++++++++++++++-
src/test/regress/sql/lock.sql      |  59 +++++++++++++++-
4 files changed, 285 insertions(+), 18 deletions(-)