cubicweb #2543960 avoid gethostname() when avoidable [open]

See also ticket #2542815.

Using gethostname() should be avoided in simple, default setups.

Use relative URLs such as:
/my/path/123
instead of full URLs:
http://localhost.localdomain/my/path/123
which you often get wrong by using gethostname() instead of getfqdn() as described in ticket #2542815:
http://localhost/my/path/123

In real life gethostname() very often does not return the correct name to be used in URLs.

priorityminor
typeenhancement
done in<not specified>
closed by<not specified>