package/syslog-ng: fix build if net-snmp is installed on the host (again)

See also commit 4ff6e5239240a4e1bdf73c41d6e9bff9473ec62c which describes the
problem in detail.

The same problem now arises again, because syslog-ng renamed the
--enable-snmp-dest option into --enable-afsnmp. See syslog-ng commit
4537938474771673ef5bd4a9cad7c9a7dc20b7c1, first part of 3.27.1.

Update the configure options passed from Buildroot accordingly.

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 40f4468e94e0c9885386b8a6ee105aed175f340f)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/syslog-ng/syslog-ng.mk

@@ -99,10 +99,10 @@ endif
 
 ifeq ($(BR2_PACKAGE_NETSNMP),y)
 SYSLOG_NG_DEPENDENCIES += netsnmp
-SYSLOG_NG_CONF_OPTS += --enable-snmp-dest
+SYSLOG_NG_CONF_OPTS += --enable-afsnmp
 SYSLOG_NG_CONF_OPTS += --with-net-snmp="$(STAGING_DIR)/usr/bin"
 else
-SYSLOG_NG_CONF_OPTS += --disable-snmp-dest
+SYSLOG_NG_CONF_OPTS += --disable-afsnmp
 endif
 
 define SYSLOG_NG_INSTALL_INIT_SYSV