source-dialog: better name the modes

Since we're not creating a calendar
as the default state, rename the mode
to NORMAL as it better describes the
dialog state.

src/gcal-source-dialog.h

@@ -42,7 +42,7 @@ struct _GcalSourceDialogClass
 typedef enum
 {
   GCAL_SOURCE_DIALOG_MODE_EDIT,
-  GCAL_SOURCE_DIALOG_MODE_CREATE
+  GCAL_SOURCE_DIALOG_MODE_NORMAL
 } GcalSourceDialogMode;
 
 GcalSourceDialog*   gcal_source_dialog_new                  (void);