configure.ac: re-bump to version 1.9.91 for the alpha release
diff --git a/configure.ac b/configure.ac
index 16735fb..2469cdb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,7 +1,7 @@
 AC_PREREQ([2.64])
 
-m4_define([wayland_major_version], [1])
-m4_define([wayland_minor_version], [9])
+m4_define([wayland_major_version],  [1])
+m4_define([wayland_minor_version],  [9])
 m4_define([wayland_micro_version], [91])
 m4_define([wayland_version],
           [wayland_major_version.wayland_minor_version.wayland_micro_version])