Check for valid columns in adodb postgres64 driver MetaIndexes fn

Bug 1384473

Indexes on functions of columns have a 0 in the indkey column of
pg_catalog.pg_index, which doesn't refer to a column.

Don't return any columns for the index, rather than returning an empty
column name.

(cherry picked from commit b87d9961020a8d52a2eaf709a9197520b3c6b65b)

Change-Id: Idd9bcdd04f15c99e76e028d62236a4d932ee845c
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
ADODB modification: add __wakeup to connection object

Bug 1384473

This reconnects to the db after wakeup, as resource types cannot be
serialized and unserialized.

This is necessary for unit tests, phpunit backups and restore globals
between each test.

(cherry picked from commit 417077459037550239fe9b09bd20b50d4c19b57f)

Change-Id: I00f38a6cf101019fb684b4f5c9b40c2d937b614d
Signed-off-by: Penny Leach <penny@mjollnir.org>
Signed-off-by: Andrew Robert Nicols <andrew.nicols@luns.net.uk>
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>