ntlm: Remove redundant ifdef USE_OPENSSL

lib/curl_ntlm.c had code that read as follows:

  #ifdef USE_OPENSSL
  # ifdef USE_OPENSSL
  # else
  # ..
  # endif
  #endif

Remove the redundant USE_OPENSSL along with #else (it's not possible to
reach it anyway). The removed construction is a leftover from when the
SSLeay support was removed.

Closes #3269
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Daniel Stenberg <daniel@haxx.se>