classes: Add dbus-dir

Export some commonly used dbus paths for use by recipes.
Similar to python-dir in the base.

Change-Id: Id3723766338e06a5c6934ab7c55524546ce582a6
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/classes/dbus-dir.bbclass b/classes/dbus-dir.bbclass
new file mode 100644
index 0000000..f663463
--- /dev/null
+++ b/classes/dbus-dir.bbclass
@@ -0,0 +1,2 @@
+dbus_system_confdir="${sysconfdir}/dbus-1/system.d/"
+dbus_system_servicesdir="${datadir}/dbus-1/system-services/"