Remove StartSSLWithServer from SSLStreamAdapter.

It's not used by anything any more. We only use SSLStreamAdapter in
the mode where it verifies the peer's certificate using a signaled
digest.

R=pthatcher@webrtc.org, zhihuang@webrtc.org

Review URL: https://codereview.webrtc.org/2204883004 .

Cr-Commit-Position: refs/heads/master@{#13730}
diff --git a/webrtc/base/sslstreamadapter_unittest.cc b/webrtc/base/sslstreamadapter_unittest.cc
index 07ee855..341e09f 100644
--- a/webrtc/base/sslstreamadapter_unittest.cc
+++ b/webrtc/base/sslstreamadapter_unittest.cc
@@ -385,10 +385,10 @@
     int rv;
 
     server_ssl_->SetServerRole();
-    rv = server_ssl_->StartSSLWithPeer();
+    rv = server_ssl_->StartSSL();
     ASSERT_EQ(0, rv);
 
-    rv = client_ssl_->StartSSLWithPeer();
+    rv = client_ssl_->StartSSL();
     ASSERT_EQ(0, rv);
 
     // Now run the handshake