Fix using "has_link()" to check nic physical connected failed issue

Previously using the "has_link" of class "NIC" to detect the physical
connected state of a network cable/connector will fail.This is due to
it miss to execute "ip link set dev {dev} up" before check "1" in
/sys/class/net/{dev}/carrier.

Change-Id: I608af3dd35d979b2213a762d84b831e792417efc
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1029033
Signed-off-by: hadong <hadong0720@gmail.com>