pgsql: Fix sepgsql regression tests (9.2-only patch).

Fix sepgsql regression tests (9.2-only patch).

The regression tests for sepgsql were broken by changes in the
base distro as-shipped policies. Specifically, definition of
unconfined_t in the system default policy was changed to bypass
multi-category rules, which the regression test depended on.
Fix that by defining a custom privileged domain
(sepgsql_regtest_superuser_t) and using it instead of system's
unconfined_t domain. The new sepgsql_regtest_superuser_t domain
performs almost like the current unconfined_t, but restricted by
multi-category policy as the traditional unconfined_t was.

The custom policy module is a self defined domain, and so should not
be affected by related future system policy changes. However, it still
uses the unconfined_u:unconfined_r pair for selinux-user and role.
Those definitions have not been changed for several years and seem
less risky to rely on than the unconfined_t domain. Additionally, if
we define custom user/role, they would need to be manually defined
at the operating system level, adding more complexity to an already
non-standard and complex regression test.

Applies only to 9.2. Unlike the previous similar patch, commit 794e2558b,
this also fixes a bug related to processing SELECT INTO statement.
Because v9.2 didn't have ObjectAccessPostCreate to inform the context
when a relation is newly created, sepgsql had an alternative method.
However, related code in sepgsql_object_access() neglected to consider
T_CreateTableAsStmt, thus no label was assigned on the new relation.
This logic was removed and replaced starting in 9.3.

Patch by Kohei KaiGai.

Branch
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REL9_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/e90a629e126b9459b1f1d8ee8aa8c8598dc36b16

Modified Files
--------------
contrib/sepgsql/expected/ddl.out | 208 ++++++++++++++++++------------------
contrib/sepgsql/expected/dml.out | 6 +-
contrib/sepgsql/expected/label.out | 106 +++++++++---------
contrib/sepgsql/hooks.c | 1 +
contrib/sepgsql/launcher | 2 +-
contrib/sepgsql/sepgsql-regtest.te | 98 ++++++++++++++---
contrib/sepgsql/sql/ddl.sql | 2 +-
contrib/sepgsql/sql/dml.sql | 2 +-
contrib/sepgsql/sql/label.sql | 20 ++--
9 files changed, 255 insertions(+), 190 deletions(-)