Fix test "server is up" detection after logging changes.

tests/assets/default.conf

@@ -1,5 +1,6 @@
 # Redis configuration for testing.
 
+always-show-logo yes
 notify-keyspace-events KEA
 daemonize no
 pidfile /var/run/redis.pid

tests/support/server.tcl

@@ -278,7 +278,7 @@ proc start_server {options {code undefined}} {
 
         while 1 {
             # check that the server actually started and is ready for connections
-            if {[exec grep "ready to accept" | wc -l < $stdout] > 0} {
+            if {[exec grep -i "Ready to accept" | wc -l < $stdout] > 0} {
                 break
             }
             after 10