Add a warning when beecrypt is selected for the crypto library

Let's make it absolutely clear that selecting beecrypt is deprecated
and those continuing to use it should be aware that the option will
go away soon.

configure.ac

@@ -269,6 +269,7 @@ AM_CONDITIONAL([WITH_BEECRYPT],[test "$with_crypto" = beecrypt])
 WITH_BEECRYPT_INCLUDE=
 WITH_BEECRYPT_LIB=
 if test "$with_crypto" = beecrypt ; then
+  AC_MSG_WARN([Using the beecrypt library with rpm is deprecated and support will be removed in a future release!])
   AC_DEFINE(WITH_BEECRYPT, 1, [Build with beecrypt instead of nss3 support?])
   if test "$with_internal_beecrypt" = yes ; then
     WITH_BEECRYPT_INCLUDE="-I\$(top_srcdir)/beecrypt"