Fix reading parameters.yml data for PostgreSQL

[jskirzynski]

Change of default PostgreSQL configuration for fix " When no parameters is specified under postgresql, the bundle taking those from parameters.yml" functionality. At this moment localhost is the default host for PostgreSQL (based on Configuration.php) and script does not read data from parameters.yml.

[Nyholm]

I like this change. Though, it breaks BC. I suggest to save this one for next major version.