Ticket 49675 - Fix coverity issues
    
    Description:  Fixed these coverity issues.  Some of these fixes are
                  just to quiet convscan:
    
    16852   Unsigned compared - entrycache_add_int
    16848   Unsigned compared - dncache_add_int
    16704   Explicit null dereferenced s- lapd_SSL_client_auth
    15953   Resource leak - new_task
    15583   Out-of-bounds read - create_filter
    15445   Unused value - ruv_update_ruv
    15442   Argument cannot be negative - dse_write_file_nolock
    15223   Double unlock - ruv_get_referrals
    15170   Explicit null dereferenced - passwd_apply_mods
    15581   Wrong sizeof argument - slapi_be_new
    15144   Constant expression result - upgradedn_producer
    
                   Also fixed a few compiler warnings
    
    https://pagure.io/389-ds-base/issue/49675
    
    Reviewed by: spichugi & lkrispenz(Thanks!!)