Fix inconsistent #include style

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
diff --git a/clients/terminal.c b/clients/terminal.c
index 092e069..df2f8c7 100644
--- a/clients/terminal.c
+++ b/clients/terminal.c
@@ -37,7 +37,7 @@
 #include <X11/keysym.h>
 
 #include "wayland-util.h"
-#include "wayland-client.h"
+#include <wayland-client.h>
 
 #include "window.h"