stratosphere-except-ldr: use fs bindings (this temporarily breaks loader)

stratosphere/fatal/source/fatal_main.cpp

@@ -103,7 +103,6 @@ void __appInit(void) {
 
 void __appExit(void) {
     /* Cleanup services. */
-    fsdevUnmountAll();
     fsExit();
     plExit();
     gpioExit();

stratosphere/fatal/source/fatal_scoped_file.hpp

@@ -28,7 +28,7 @@ namespace ams::fatal::srv {
         public:
             ScopedFile(const char *path) : file(), offset(), opened(false) {
                 if (R_SUCCEEDED(fs::CreateFile(path, 0))) {
-                    this->opened = R_SUCCEEDED(fs::OpenFile(std::addressof(this->file), path, fs::OpenMode_Write | fs::OpenMode_Append));
+                    this->opened = R_SUCCEEDED(fs::OpenFile(std::addressof(this->file), path, fs::OpenMode_Write | fs::OpenMode_AllowAppend));
                 }
             }