Allow a plugin specific interface_driver config in q-lbaas

Previously interface_driver for q-lbaas is hardcoded and q-lbaas does
not work when quantum plugin requires additional configuration (like
ovs_use_veth=True). This commit set up interface_driver using
quantum_plugin_setup_interface_driver function.

This commit also moves a script related Quantum service plugin to
lib/quantum_plugins/services/

Change-Id: Iad11c1b31071dfb580843be18be78c83feb91f10
diff --git a/lib/quantum_plugins/services/agent_loadbalancer b/lib/quantum_plugins/services/agent_loadbalancer
new file mode 100644
index 0000000..b6528b0
--- /dev/null
+++ b/lib/quantum_plugins/services/agent_loadbalancer
@@ -0,0 +1,45 @@
+# Quantum loadbalancer plugin
+# ---------------------------
+
+# Save trace setting
+MY_XTRACE=$(set +o | grep xtrace)
+set +o xtrace
+
+
+AGENT_LBAAS_BINARY="$QUANTUM_DIR/bin/quantum-lbaas-agent"
+AGENT_LBAAS_PLUGIN=quantum.plugins.services.agent_loadbalancer.plugin.LoadBalancerPlugin
+
+function quantum_agent_lbaas_install_agent_packages() {
+    if is_ubuntu || is_fedora; then
+        install_package haproxy
+    elif is_suse; then
+        ### FIXME: Find out if package can be pushed to Factory
+        echo "HAProxy packages can be installed from server:http project in OBS"
+    fi
+}
+
+function quantum_agent_lbaas_configure_common() {
+    if [[ $Q_SERVICE_PLUGIN_CLASSES == '' ]]; then
+        Q_SERVICE_PLUGIN_CLASSES=$AGENT_LBAAS_PLUGIN
+    else
+        Q_SERVICE_PLUGIN_CLASSES="$Q_SERVICE_PLUGIN_CLASSES,$AGENT_LBAAS_PLUGIN"
+    fi
+}
+
+function quantum_agent_lbaas_configure_agent() {
+    LBAAS_AGENT_CONF_PATH=/etc/quantum/plugins/services/agent_loadbalancer
+    mkdir -p $LBAAS_AGENT_CONF_PATH
+
+    LBAAS_AGENT_CONF_FILENAME="$LBAAS_AGENT_CONF_PATH/lbaas_agent.ini"
+
+    cp $QUANTUM_DIR/etc/lbaas_agent.ini $LBAAS_AGENT_CONF_FILENAME
+
+    quantum_plugin_setup_interface_driver $LBAAS_AGENT_CONF_FILENAME
+
+    if is_fedora; then
+        iniset $LBAAS_AGENT_CONF_FILENAME DEFAULT user_group "nobody"
+    fi
+}
+
+# Restore xtrace
+$MY_XTRACE