Create overloaded constructor instead of default arguments (#159)

Summary:
Pull Request resolved: #159

Per discussion in D34216915, we should not make breaking API changes like this.

This diff creates the overloaded constructor. Note that this is a no-op because both versions continue to exist.

We are splitting up the two diffs because they are in different repositories (although in theory it is a safe change and shouldn't matter)

Reviewed By: chualynn

Differential Revision: D35198992

fbshipit-source-id: fb8aad9e857c261a9ba82cb7f93e6b9335b10610

fbpcf/mpc/EmpApp.h

@@ -24,14 +24,21 @@ class EmpApp {
       Party party,
       const std::string& serverIp,
       uint16_t port,
-      bool useTls = false,
-      const std::string& tlsDir = "")
+      bool useTls,
+      const std::string& tlsDir)
       : party_{party},
         serverIp_{serverIp},
         port_{port},
         useTls_{useTls},
         tlsDir_{tlsDir} {}
 
+  EmpApp(Party party, const std::string& serverIp, uint16_t port)
+      : party_{party},
+        serverIp_{serverIp},
+        port_{port},
+        useTls_{false},
+        tlsDir_{""} {}
+
   virtual ~EmpApp(){};
 
   virtual void run() {
@@ -56,6 +63,6 @@ class EmpApp {
   uint16_t port_; // Port to bind to, or port to connect to (for publisher or
                   // partner respectively)
   bool useTls_; // whether to use TLS for communication
-  const std::string& tlsDir_; // directory that holds the TLS certificates/keys
+  const std::string tlsDir_; // directory that holds the TLS certificates/keys
 };
 } // namespace fbpcf