fix PdoNuoDbHandle::setOptions to handle NULLs
add test case for bad DSN database name
Fix expected exception message
Add checks for NULL database, user, password
Improve DSN tests
Fix warning on assignment of einfo->file
Merge branch 'tgates/DB-4665'

* tgates/DB-4665:
  Fix warning on assignment of einfo->file
  Improve DSN tests
  Add checks for NULL database, user, password
  Fix expected exception message
  add test case for bad DSN database name
  fix PdoNuoDbHandle::setOptions to handle NULLs