Allow install os-vif library used by Nova

In future Nova will use os-vif library for some communication with Neutron.
This patch add ability to install os-vif library that requires for run
tempest-jobs for new patches, that used os-vif.

Change-Id: I28e48afd3c740b1aa50c994d99f660f095e7deda
diff --git a/lib/nova b/lib/nova
index 3a5a47f..2b8fefa 100644
--- a/lib/nova
+++ b/lib/nova
@@ -34,6 +34,7 @@
 
 # Set up default directories
 GITDIR["python-novaclient"]=$DEST/python-novaclient
+GITDIR["os-vif"]=$DEST/os-vif
 NOVA_DIR=$DEST/nova
 
 # Nova virtual environment
@@ -728,6 +729,13 @@
 
 # install_nova() - Collect source and prepare
 function install_nova {
+
+    # Install os-vif
+    if use_library_from_git "os-vif"; then
+        git_clone_by_name "os-vif"
+        setup_dev_lib "os-vif"
+    fi
+
     if is_service_enabled n-cpu && [[ -r $NOVA_PLUGINS/hypervisor-$VIRT_DRIVER ]]; then
         install_nova_hypervisor
     fi