Fix several warnings that appear in gcc 4.3.2.

Fix several warnings that appear in gcc 4.3.2.

None of them seem very important, but this leaves us "almost" warning-free

There's still a scary warning that remains:

crypto/wvsslhacks.c: In function ‘wv_i2d_OCSP_REQUEST_bio’:
crypto/wvsslhacks.c:48: warning: function called through a non-compatible type
crypto/wvsslhacks.c:48: note: if this code is reached, the program will abort

I have no idea what it's talking about.  'make test' passes, at least,
though I don't really know if it tests that function or not.