Add a missing #include. Remove an unnecessary #include.

Summary:
'Nuf said.

Depends on D4413112

Reviewed By: yfeldblum, spacedentist

Differential Revision: D4425605

fbshipit-source-id: a7c98867cfa5c859a1b4d2eb78724710c4f1115f

folly/io/async/AsyncSocketException.h

@@ -16,6 +16,8 @@
 
 #pragma once
 
+#include <stdexcept>
+
 #include <folly/Format.h>
 #include <folly/io/async/DelayedDestruction.h>
 

folly/io/async/ssl/SSLErrors.h

@@ -15,7 +15,6 @@
  */
 #pragma once
 
-#include <folly/Optional.h>
 #include <folly/io/async/AsyncSocketException.h>
 
 namespace folly {