pgsql: Centralize some ALTER .. SET SCHEMA checks.

Centralize some ALTER <whatever> .. SET SCHEMA checks.

Any flavor of ALTER <whatever> .. SET SCHEMA fails if (1) the object
is already in the new schema, (2) either the old or new schema is
a temp schema, or (3) either the old or new schema is the TOAST schema.

Extraced from a patch by Dimitri Fontaine, with additional hacking by me.

Branch
------
master

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=44475e782f4674d257b9e5c1a3930218a4b4deea

Modified Files
--------------
src/backend/catalog/dependency.c    |   15 +++++++++++++++
src/backend/catalog/namespace.c     |   34 ++++++++++++++++++++++++++++++++++
src/backend/commands/functioncmds.c |   20 ++------------------
src/backend/commands/tablecmds.c    |   20 ++------------------
src/backend/commands/typecmds.c     |   20 ++------------------
src/include/catalog/dependency.h    |    1 +
src/include/catalog/namespace.h     |    2 ++
7 files changed, 58 insertions(+), 54 deletions(-)