HPCC-12488 LDAP Security core if reference uninitialized member

If the CLDAPGetValuesLenWrapper class gets constructed via the ctor that
accepts arguments, bvalues does not get initialized and can core later when
calling getValues. This fix initializes that member in both constructors.

Signed-off-by: William Whitehead <william.whitehead@lexisnexis.com>
Merge pull request #6588 from RussWhitehead/getValues

HPCC-12488 LDAP Security core if reference uninitialized member

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>