Update documentation for DSA_SIG and ECDSA_SIG.

RT#4590
Reviewed-by: NRich Salz <rsalz@openssl.org>

doc/crypto/DSA_SIG_new.pod

@@ -16,7 +16,7 @@ DSA_SIG_new, DSA_SIG_free - allocate and free DSA signature objects
 
 =head1 DESCRIPTION
 
-DSA_SIG_new() allocates and initializes a B<DSA_SIG> structure.
+DSA_SIG_new() allocates an empty B<DSA_SIG> structure.
 
 DSA_SIG_free() frees the B<DSA_SIG> structure and its components. The
 values are erased before the memory is returned to the system.

doc/crypto/ECDSA_SIG_new.pod

@@ -47,8 +47,8 @@ L<EVP_DigestSignInit(3)> or L<EVP_DigestVerifyInit(3)> instead.
 B<ECDSA_SIG> is an opaque structure consisting of two BIGNUMs for the
 B<r> and B<s> value of an ECDSA signature (see X9.62 or FIPS 186-2).
 
-ECDSA_SIG_new() allocates a new B<ECDSA_SIG> structure (note: this
-function also allocates the BIGNUMs) and initializes it.
+ECDSA_SIG_new() allocates an empty B<ECDSA_SIG> structure. Note: before
+OpenSSL 1.1.0 the: the B<r> and B<s> components were initialised.
 
 ECDSA_SIG_free() frees the B<ECDSA_SIG> structure B<sig>.