pgsql: Correctly init/deinit recovery xact environment.

Correctly init/deinit recovery xact environment.
Previously we performed VirtualXactLockTableInsert
but didn't set MyProc->lxid for Startup process.
pg_locks now correctly shows "1/1" for vxid
of Startup process during Hot Standby.
At end of Hot Standby the Virtual Transaction
was not deleted, leading to problems after
promoting to normal running for some commands,
such as CREATE INDEX CONCURRENTLY.

Branch
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REL9_1_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/6f9a9da85c9015e773d12e8571c469e5a2a6b3fb

Modified Files
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src/backend/storage/ipc/standby.c | 9 ++++++++-
src/backend/storage/lmgr/lmgr.c | 18 ++++++++++++++++++
src/include/storage/lmgr.h | 1 +
3 files changed, 27 insertions(+), 1 deletions(-)