Bug 613056 - fix coverify Defect Type: Null pointer dereferences
    issues 11892 - 11939
    
    https://bugzilla.redhat.com/show_bug.cgi?id=613056
    Resolves: bug 613056
    Bug description: Fix coverify Defect Type: Null pointer dereferences
    issues 11892 - 11939
    description: Catch possible NULL pointer in slapi_entry_syntax_check()
    and slapi_mods_syntax_check().
    Note: reverted the previous fix and added a NULL pb check to make
    coverity happy.  The functions slapi_entry_syntax_check and
    slapi_mods_syntax_check are designed to allow NULL pb.
    coverity ID: 11900