Deal with host whitelists for print module

[dwins]

The print configuration (config.yaml) has a whitelist of hosts that can be accessed to get print map tiles from. When custom maps are created, the config somehow has to add their hosts to the whitelist.

An alternative solution would be to not use whitelists, but then the print service would be open to print maps created of tiles from any server.

[ingenieroariel]

Note: OpenGeo has been investigating alternatives to the MapFish Printing service for use with GeoNode - that alternative might make this issue irrelevant.

[ingenieroariel]

This has been fixed with the creation of the geonode-updateip command. It deals with adding the local host to the whitelist.