ola: fix compilation with musl 1.2.3

musl 1.2.3 defines NULL as nullptr. Cannot use reinterpret_cast with nullptr.

No idea why this is even here. NULL in C == 0.

Author: neheb

ola/AutoStart.cpp

@@ -110,11 +110,7 @@ TCPSocket *ConnectToServer(unsigned short port) {
     // Try to start the server, we pass --daemon (fork into background) and
     // --syslog (log to syslog).
     execlp("olad", "olad", "--daemon", "--syslog",
-#ifdef __FreeBSD__
            reinterpret_cast<char*>(0));
-#else
-           reinterpret_cast<char*>(NULL));
-#endif  // __FreeBSD__
     OLA_WARN << "Failed to exec: " << strerror(errno);
     _exit(1);
   }