DebuggerInterface: reset port IDs on Close()...

...and add accessor to detect whether we currently have a valid
connection or not.

src/apps/debugger/debugger_interface/DebuggerInterface.cpp

@@ -316,6 +316,9 @@ DebuggerInterface::Close(bool killTeam)
 
 	if (fDebuggerPort >= 0)
 		delete_port(fDebuggerPort);
+
+	fNubPort = -1;
+	fDebuggerPort = -1;
 }
 
 

src/apps/debugger/debugger_interface/DebuggerInterface.h

@@ -38,6 +38,9 @@ public:
 			status_t			Init();
 			void				Close(bool killTeam);
 
+			bool				Connected() const
+									{ return fNubPort >= 0; }
+
 			Architecture*		GetArchitecture() const
 									{ return fArchitecture; }