configure.in incorrectly changes BACK_LDAP (ITS#2608)

[sfrost@snowman.net]

Full_Name: Stephen Frost
Version: 2.1.21
OS: Debian
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (68.100.229.246)


In the configure.in (and thus, in configure itself) is a bug whereby if you
enable BACK_LDAP to be a dynamically built module and also enable BACK_META,
BACK_LDAP will end up getting set to 'yes' even though it was set to 'mod'
before.  Due to this it is apparently not possible to build both BACK_META and
BACK_LDAP as modules.  I've fixed this in both configure.in and configure in the
Debian SVN repository.  A patch is located at:
http://snowman.net/fix_meta.diff
You may need to only apply the part which modifies the configure.in.