pgsql: Create new errcode for recovery conflict caused by db drop on ma

Create new errcode for recovery conflict caused by db drop on master.
Previously reported as ERRCODE_ADMIN_SHUTDOWN, this case is now
reported as ERRCODE_T_R_DATABASE_DROPPED. No message text change.
Unlikely to happen on most servers, so low impact change to allow
session poolers to correctly handle this situation.

Tatsuo Ishii, edits by me, review by Robert Haas

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=9e95c9ad558bafa26efbab50f77929de4ade5f90

Modified Files
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doc/src/sgml/errcodes.sgml | 5 +++++
src/backend/tcop/postgres.c | 4 +++-
src/include/utils/errcodes.h | 1 +
src/pl/plpgsql/src/plerrcodes.h | 4 ++++
4 files changed, 13 insertions(+), 1 deletions(-)