DBus: Use org.gnome prefix and adapt to changes

In preparation to moving to GNOME all the IDs, DBus object paths, etc should
change.

src/dbus/meson.build

@@ -2,8 +2,8 @@ generated_dbus_sources = []
 
 # DBus server protocols
 generated_dbus_sources += gnome.gdbus_codegen('calls-call-dbus',
-                'sm.puri.Calls.Call.xml',
+                'org.gnome.Calls.Call.xml',
                 docbook: 'calls',
-                interface_prefix: 'sm.puri',
+                interface_prefix: 'org.gnome',
                 object_manager: true,
                 namespace: 'CallsDBus')

src/dbus/org.gnome.Calls.Call.xml

@@ -21,7 +21,7 @@
 
 <node>
 
-  <interface name="sm.puri.Calls.Call">
+  <interface name="org.gnome.Calls.Call">
     <method name="Accept"/>
     <method name="Hangup"/>
     <property name="Inbound" type="b" access="read"/>