BUILD: Explicitly link libsss_ad.so with sasl libs
    
    If openldap is not built with sasl support
    libsss_ad.so will not be linked with libsasl2 although
    sasl_client_init is called by function ad_sasl_initialize.
    
    (cherry picked from commit c3889e5a101a075defe533d81f5296d5e680f639)