free NULL cleanup 7

This gets BN_.*free:
    BN_BLINDING_free BN_CTX_free BN_FLG_FREE BN_GENCB_free
    BN_MONT_CTX_free BN_RECP_CTX_free BN_clear_free BN_free BUF_MEM_free

Also fix a call to DSA_SIG_free to ccgost engine and remove some #ifdef'd
dead code in engines/e_ubsec.

Reviewed-by: Richard Levitte <levitte@openssl.org>
diff --git a/test/dhtest.c b/test/dhtest.c
index 35bd298..8f71723 100644
--- a/test/dhtest.c
+++ b/test/dhtest.c
@@ -201,8 +201,7 @@
         OPENSSL_free(bbuf);
     DH_free(b);
     DH_free(a);
-    if (_cb)
-        BN_GENCB_free(_cb);
+    BN_GENCB_free(_cb);
     BIO_free(out);
 # ifdef OPENSSL_SYS_NETWARE
     if (ret)