options: Parse hostname by last '@'

The login name can have '@' char in it

Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
(cherry picked from commit bb5f7e2707)

src/options.c

@@ -513,7 +513,7 @@ int ssh_options_set(ssh_session session, enum ssh_options_e type,
                     ssh_set_error_oom(session);
                     return -1;
                 }
-                p = strchr(q, '@');
+                p = strrchr(q, '@');
 
                 SAFE_FREE(session->opts.host);