Add missing filter to secondary test config

The test configs weren't similar.

test/maxscale_test_secondary.cnf

@@ -51,6 +51,7 @@ router_options=master
 servers=server1
 user=maxuser
 password=maxpwd
+filters=QLA
 
 [Hint]
 type=filter
@@ -71,6 +72,14 @@ type=filter
 module=tee
 service=RW-Split-Hint-Router
 
+[QLA]
+type=filter
+module=qlafilter
+log_type=unified
+append=false
+flush=true
+filebase=/tmp/qla2.log
+
 [CLI]
 type=service
 router=cli