free NULL cleanup 11

Don't check for NULL before calling free functions. This gets:
        ERR_STATE_free
        ENGINE_free
        DSO_free
        CMAC_CTX_free
        COMP_CTX_free
        CONF_free
        NCONF_free NCONF_free_data _CONF_free_data
        A sk_free use within OBJ_sigid_free
        TS_TST_INFO_free (rest of TS_ API was okay)
        Doc update for UI_free (all uses were fine)
        X509V3_conf_free
        X509V3_section_free
        X509V3_string_free

Reviewed-by: Richard Levitte <levitte@openssl.org>