Set default db schema search path to public,pg_catalog

Set default db schema search path to public,pg_catalog

With the addition of the 'evergreen' schema, we discovered that
all of the unqualified database objects were being created in
the 'evergreen' schema if the database user name was 'evergreen'
(as the default search path is "$user",public we started matching
"$user").

Thomas Berezansky proposed a variation of the function provided
here for changing database settings. By creating the function in
the first schema file, the subsequent connections pick up the
new default search path and all works blissfully as it once did.

Long term, we should probably move towards explicitly qualified
database objects.

git-svn-id: svn://svn.open-ils.org/ILS/trunk@19759 dcc99617-32d9-48b4-a31d-7c20da2025e4