crash due to use_citusdb_select_logic on postgres is fixed (#10)
Update error message

When the "use_citusdb_select_logic" configuration parameter is set
to "true" on postgres, an error report is produced. This commit is
done for updating the error report.
White space change

According to CitusDB coding conventions, it is required to have a space
after "if".
Merge pull request #29 from citusdata/feature/citus_integration#10

Crash due to use_citusdb_select_logic on postgres is fixed

cr: @jasonmp85