server: add missing IOLOG command to text list

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/server.c b/server.c
index 7ab01ef..9110707 100644
--- a/server.c
+++ b/server.c
@@ -55,6 +55,7 @@
 	"SERVER_START",
 	"ADD_JOB",
 	"CMD_RUN"
+	"CMD_IOLOG",
 };
 
 const char *fio_server_op(unsigned int op)