crypto: try moving read head in Peek()

Otherwise it might get stall (`Peek()` will return zero-length chunk)
in following situation:

1. `Write(kBufferLength)`
2. `Read(kBufferLength)`
3. `Write(anything)`
4. `Peek()` => `len=0`
crypto: unbreak build with no-NPN shared openssl

Unbreak the build when linking against a shared version of OpenSSL that
doesn't support NPN (Next Protocol Negotiation.)

Fixes the following build error:

  ../src/node_crypto.cc:140: error: no member function
  'AdvertiseNextProtoCallback' declared in
  'node::crypto::SSLWrap<node::TLSCallbacks>'
  ../src/node_crypto.cc:147: error: no member function
  'SelectNextProtoCallback' declared in
  'node::crypto::SSLWrap<node::TLSCallbacks>'
Merge branch 'master' of github.com:joyent/node