Error in trace file suspend counter not zero

When importing from OFX, an error can be seen in the trace file when
gnc_gui_refresh_all is called when refresh is suspended. Add a check
for refresh being suspended before calling for a refresh.

gnucash/import-export/import-main-matcher.cpp

@@ -247,6 +247,7 @@ gnc_gen_trans_list_delete (GNCImportMainMatcher *info)
 
     g_free (info);
 
+    if (!gnc_gui_refresh_suspended ())
         gnc_gui_refresh_all ();
 }