configure.in : Fix a wrong comment.

configure.in:
  Fix a wrong comment (as of 5.1, there is no separate keeping of NDB version numbers).

configure.in

@@ -6,7 +6,7 @@ AC_PREREQ(2.52)dnl		Minimum Autoconf version required.
 AC_INIT(sql/mysqld.cc)
 AC_CANONICAL_SYSTEM
 # The Docs Makefile.am parses this line!
-# remember to also change ndb version below and update version.c in ndb
+# remember to also update version.c in ndb
 AM_INIT_AUTOMAKE(mysql, 5.1.15-beta)
 AM_CONFIG_HEADER(config.h)