Enforce function declaration format in bash8

Check that function calls look like ^function foo {$ in bash8, and fix
all existing failures of that check.  Add a note to HACKING.rst

Change-Id: Ic19eecb39e0b20273d1bcd551a42fe400d54e938
diff --git a/lib/neutron_plugins/midonet b/lib/neutron_plugins/midonet
index dd3b2ba..742e3b2 100644
--- a/lib/neutron_plugins/midonet
+++ b/lib/neutron_plugins/midonet
@@ -9,32 +9,32 @@
 MY_XTRACE=$(set +o | grep xtrace)
 set +o xtrace
 
-function is_neutron_ovs_base_plugin() {
+function is_neutron_ovs_base_plugin {
     # MidoNet does not use l3-agent
     # 0 means True here
     return 1
 }
 
-function neutron_plugin_create_nova_conf() {
+function neutron_plugin_create_nova_conf {
     NOVA_VIF_DRIVER=${NOVA_VIF_DRIVER:-"nova.virt.libvirt.vif.LibvirtGenericVIFDriver"}
 }
 
-function neutron_plugin_install_agent_packages() {
+function neutron_plugin_install_agent_packages {
     :
 }
 
-function neutron_plugin_configure_common() {
+function neutron_plugin_configure_common {
     Q_PLUGIN_CONF_PATH=etc/neutron/plugins/midonet
     Q_PLUGIN_CONF_FILENAME=midonet.ini
     Q_DB_NAME="neutron_midonet"
     Q_PLUGIN_CLASS="neutron.plugins.midonet.plugin.MidonetPluginV2"
 }
 
-function neutron_plugin_configure_debug_command() {
+function neutron_plugin_configure_debug_command {
     :
 }
 
-function neutron_plugin_configure_dhcp_agent() {
+function neutron_plugin_configure_dhcp_agent {
     DHCP_DRIVER=${DHCP_DRIVER:-"neutron.plugins.midonet.agent.midonet_driver.DhcpNoOpDriver"}
     neutron_plugin_setup_interface_driver $Q_DHCP_CONF_FILE
     iniset $Q_DHCP_CONF_FILE DEFAULT dhcp_driver $DHCP_DRIVER
@@ -42,15 +42,15 @@
     iniset $Q_DHCP_CONF_FILE DEFAULT enable_isolated_metadata True
 }
 
-function neutron_plugin_configure_l3_agent() {
+function neutron_plugin_configure_l3_agent {
     die $LINENO "q-l3 must not be executed with MidoNet plugin!"
 }
 
-function neutron_plugin_configure_plugin_agent() {
+function neutron_plugin_configure_plugin_agent {
     die $LINENO "q-agt must not be executed with MidoNet plugin!"
 }
 
-function neutron_plugin_configure_service() {
+function neutron_plugin_configure_service {
     if [[ "$MIDONET_API_URL" != "" ]]; then
         iniset /$Q_PLUGIN_CONF_FILE MIDONET midonet_uri $MIDONET_API_URL
     fi
@@ -68,17 +68,17 @@
     Q_L3_ROUTER_PER_TENANT=True
 }
 
-function neutron_plugin_setup_interface_driver() {
+function neutron_plugin_setup_interface_driver {
     local conf_file=$1
     iniset $conf_file DEFAULT interface_driver neutron.agent.linux.interface.MidonetInterfaceDriver
 }
 
-function has_neutron_plugin_security_group() {
+function has_neutron_plugin_security_group {
     # 0 means True here
     return 0
 }
 
-function neutron_plugin_check_adv_test_requirements() {
+function neutron_plugin_check_adv_test_requirements {
     # 0 means True here
     return 1
 }