Attach sdevent mainloop to dbus

Switch from sd_bus process to sd_event run so that sd event
handlers are invoked.

Change-Id: If7c1f046f30cc845c6e9fcc72eb99c5bdfb36052
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/src/sdevent.hpp b/src/sdevent.hpp
index be8b510..dc912c1 100644
--- a/src/sdevent.hpp
+++ b/src/sdevent.hpp
@@ -3,6 +3,8 @@
 #include "sdevent/event.hpp"
 #include "sdevent/timer.hpp"
 
+struct Loop;
+
 namespace phosphor
 {
 namespace dbus
@@ -29,6 +31,8 @@
         {
             return getEvent().now();
         }
+
+        friend Loop;
 };
 
 /** @class SDEventTimer