fs/io/FileOutputStream: move code to Open()

src/fs/io/FileOutputStream.cxx

@@ -34,6 +34,12 @@
 FileOutputStream::FileOutputStream(Path _path, Mode _mode)
 	:path(_path), mode(_mode)
 {
+	Open();
+}
+
+inline void
+FileOutputStream::Open()
+{
 	switch (mode) {
 	case Mode::CREATE:
 		OpenCreate(false);

src/fs/io/FileOutputStream.hxx

@@ -133,6 +133,7 @@ public:
 private:
 	void OpenCreate(bool visible);
 	void OpenAppend(bool create);
+	void Open();
 
 	bool Close() noexcept {
 		assert(IsDefined());