Fixes #1304. The Connection instance may be destroyed by abort() when process.nextTick is executed.

lib/tls.js

@@ -496,7 +496,10 @@ function SecurePair(credentials, isServer, requestCert, rejectUnauthorized) {
   this.encrypted = new EncryptedStream(this);
 
   process.nextTick(function() {
-    self.ssl.start();
+    /* The Connection may be destroyed by an abort call */
+    if (self.ssl) {
+      self.ssl.start();
+    }
     self.cycle();
   });
 }