Prevent "Save before closing" dialog from appearing at startup.

Caused by simply loading the transaction report, which called
gnc-get-current-book and that it in turn creates a session if one
doesn't already exist.

gnucash/report/standard-reports/transaction.scm

@@ -210,7 +210,8 @@ options specified in the Options panels."))
                                    (cons 'tip (_ "Sort by description."))
                                    (cons 'renderer-fn #f)))
 
-        (if (qof-book-use-split-action-for-num-field (gnc-get-current-book))
+        (if (and (gnc-current-session-exist)
+                 (qof-book-use-split-action-for-num-field (gnc-get-current-book)))
             (cons 'number    (list (cons 'sortkey (list SPLIT-ACTION))
                                    (cons 'split-sortvalue #f)
                                    (cons 'text (_ "Number/Action"))

libgnucash/engine/engine.i

@@ -31,6 +31,7 @@
 #include "gnc-filepath-utils.h"
 #include "gnc-pricedb.h"
 #include "gnc-lot.h"
+#include "gnc-session.h"
 #include "gnc-hooks-scm.h"
 #include "engine-helpers.h"
 #include "engine-helpers-guile.h"
@@ -187,6 +188,7 @@ SplitList * qof_query_run_subquery (QofQuery *q, const QofQuery *q);
 
 %typemap(in) QofQueryParamList * "$1 = gnc_query_scm2path($input);"
 
+%include <gnc-session.h>
 %include <Query.h>
 %ignore qof_query_run;
 %ignore qof_query_last_run;