make InetAddress.getLocalHost() and hello_name usage consistent across the application

We currently (in trunk) have the following usages:

A. core.AbstractJamesService.

• read the helloName configuration.
• if autodetect is true then try "InetAddress.getLocalHost().getHostName()" and on exception "localhost"
• otherwise it uses the "localhost" child of helloHame.

B. dnsserver.DNSServer.

• in initialize(), if no dnsserver has been added try to add "InetAddress.getLocalHost().getHostName()" and revert to "127.0.0.1" on exception

C. fetchmail.MessageProcessor

• computing a remote address, if it does not find the domain part it append the localhost and calulate it this way:
  InetAddress.getByName(InetAddress.getByName(InetAddress.getLocalHost().getHostAddress()).getHostName()).getHostName() and default to "[127.0.0.1]" on exception.

D. fetchmail.ParsedConfiguration

• to compute default domain name: InetAddress.getByName(InetAddress.getLocalHost().getHostAddress()).getHostName(); and defaults to "localhost" on exception

E. transport.mailets.AbstractRedirect, AbstractVirtualUserTable, DSNBounce

• to set the RemoteAddr and RemoteHost for a locally generated mail: java.net.InetAddress.getLocalHost().getHostAddress() with fallback to "127.0.0.1" and InetAddress.getLocalHost().getHostName() with fallback to "localhost".

F. transport.mailets.RemoteDelivery and DSNBounce

• to set the text part of a bounce message InetAddress.getLocalHost().getHostName() and fallback to [address unknown] (replace "[machine]" machine pattern with the result of the localhost).

G. James

• hostname = InetAddress.getLocalHost().getHostName() with fallback to "localhost".
• put this in DefaultContext in the "HostName" key: not used by anyone.
• if <servernames>/<autodetect> is true and hostname is not "localhost" add it to servernames (but lowercase it before).
• use it as fallback as domain part of postmaster if no other servername (not autodected and not "localhost" has been found).

I'll try to define a proposal to fix this, later. Now I just wanted to share the result of a code review about this issue.