Merge pull request #2360 from sfackler/fix-alpn-lifetimes

///

/// [`SslContextBuilder::set_alpn_protos`]: struct.SslContextBuilder.html#method.set_alpn_protos

#[corresponds(SSL_select_next_proto)]

pub fn select_next_proto<'a>(server: &[u8], client: &'a [u8]) -> Option<&'a [u8]> {

pub fn select_next_proto<'a>(server: &'a [u8], client: &'a [u8]) -> Option<&'a [u8]> {

    unsafe {

        let mut out = ptr::null_mut();

        let mut outlen = 0;