Nicer looking exit when blockchain.bin is found

Do not print the exception message, and write the important bit
in red, since people will only read the last line otherwise.

src/daemon/core.h

@@ -66,15 +66,16 @@ public:
     m_core.set_cryptonote_protocol(&protocol);
   }
 
-  void run()
+  bool run()
   {
     //initialize core here
     LOG_PRINT_L0("Initializing core...");
     if (!m_core.init(m_vm_HACK))
     {
-      throw std::runtime_error("Failed to initialize core");
+      return false;
     }
     LOG_PRINT_L0("Core initialized OK");
+    return true;
   }
 
   cryptonote::core & get()

src/daemon/daemon.cpp

@@ -118,7 +118,8 @@ bool t_daemon::run(bool interactive)
 
   try
   {
-    mp_internals->core.run();
+    if (!mp_internals->core.run())
+      return false;
     mp_internals->rpc.run();
 
     daemonize::t_command_server* rpc_commands;