rt-table.c: Solution for missing igp_metric described in issue #154.

rt-table.c: Solution for missing igp_metric described in issue #154.
The igp_metric was set as an eattr, but not as a hostentry attribut.
However, the eattr was ignored and possibly even rewritten to
the hostentry (default) value.
The hostentry is initialized in ea_set_hostentry. There is an ea_list,
but it is not used for setting the igp_metric and it seems like it
does not contain the igp_metric at all. That is why I set it in rt_next_hop_resolve_rte.