Fix VMware Hyper can't honor hw_vif_model image property.

Support setting instance vif model through image property,
change default vif model to e1000. Available vif model options
for VMware Hyperv is "VirtualE1000, VirtualPCNet32, VirtualVmxnet".
Also this patch removes the unused list_interface method and tests.

DocImpact
Fix bug #1183192
Fix bug #1187251

Change-Id: I3a98bc26df7e2252bf043a71acbba2a158e213b8
(cherry picked from commit 088995fc2c792d6d029abd0e45d5c0cf09a5125a)