Use updated postgres string escaping for byte arrays.

Switching to using E'\\000'::bytea rather than just '\\000' when
escaping byte arrays.  Old syntax wasn't supported at all in 9.1,
and new is supported as far back as 8.2.

lib/arjdbc/postgresql/adapter.rb

@@ -591,7 +591,7 @@ def quote(value, column = nil) #:nodoc:
         "'#{value}'"
       when String
         case column.sql_type
-        when 'bytea' then "'#{escape_bytea(value)}'"
+        when 'bytea' then "E'#{escape_bytea(value)}'::bytea"
         when 'xml'   then "xml '#{quote_string(value)}'"
         when /^bit/
           case value