perf db-export: Get rid of db_export__deferred()

db_export__deferred() deferred the export of comms if the comm string
had not been "set" (changed from :<pid>) however that problem was fixed
a long time ago by commit e803cf97a4 ("perf record: Synthesize COMM
event for a command line workload"), so get rid of
db_export__deferred().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20190710085810.1650-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/scripting-engines/trace-event-python.c

@@ -1620,9 +1620,7 @@ error:
 
 static int python_flush_script(void)
 {
-	struct tables *tables = &tables_global;
-
-	return db_export__flush(&tables->dbe);
+	return 0;
 }
 
 /*