tests: remove (long deprecated) glueoutputbuf option from redis-test.conf

this option was removed completely starting redis 2.6

Author: mrzor

test/redis-test.conf

@@ -112,4 +112,4 @@ databases 16
 # Glue small output buffers together in order to send small replies in a
 # single TCP packet. Uses a bit more CPU but most of the times it is a win
 # in terms of number of queries per second. Use 'yes' if unsure.
-glueoutputbuf yes
+# glueoutputbuf yes