p2v: Print config->output_connection field in conversion debug.

This fixes commit 81d3aee0713faddc320cd1db5ac125891d07a0f0.
p2v: Support for interface to network map.

Instead of having all interfaces connect to the "default" network on
the hypervisor target, you can now create a map of interface to target
network, either on the kernel command line, eg:

  p2v.network=em1:rhevm
  p2v.network=em1:rhevm,em2:management,other

or through the GUI.
Version 1.27.36.