Some of the functions in this manual need <openssl/dsa.h>, others

Some of the functions in this manual need <openssl/dsa.h>, others
need <openssl/x509.h>. The functions {d2i,i2d}_DSA_params_{bio,fp}(3)
were missing from the manual, so document them. The return values
of the i2d_* functions are left undocumented, as these still need to
be audited.

ok schwarze (lots of input and help as usual)