avoid reading ifcfg files in netinfo

getting runtime network information is better via quering
more standard netinfo api's rather than reading ifcfg configuration
files which is more error prone.

We need to confine reading ifcfg files only in the context of
dealing with the ifcfg configurator.

Change-Id: I28e2084a15e1f6cc0cb4f20e83d7751fd8ffe37f
Signed-off-by: ibarkan <ibarkan@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/35043
Reviewed-by: Ondřej Svoboda <osvoboda@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>