Remove copyright from gsad version output

[davidak]

Fixes #1375

I don't have a dev environment, so please test it!

Checklist:

• [] Tests
• CHANGELOG Entry

[bjoernricks]

diff --git a/gsad/src/gsad.c b/gsad/src/gsad.c
index f176b62ea..1eed5d547 100644
--- a/gsad/src/gsad.c
+++ b/gsad/src/gsad.c
@@ -2830,6 +2827,9 @@ main (int argc, char **argv)
 
   option_context =
     g_option_context_new ("- Greenbone Security Assistant Daemon");
+
+  g_option_context_set_summary (option_context, COPYRIGHT);
+
   g_option_context_add_main_entries (option_context, option_entries, NULL);
   if (!g_option_context_parse (option_context, &argc, &argv, &error))
     {