LittleFS: Use default implementation of ::exists().

This fixes the log spam when calling LittleFS::exists() on a
non-existing file.

Author: rtrbt

libraries/LittleFS/src/LittleFS.cpp

@@ -36,19 +36,19 @@ class LittleFSImpl : public VFSImpl
 public:
     LittleFSImpl();
     virtual ~LittleFSImpl() { }
-    virtual bool exists(const char* path);
+    //virtual bool exists(const char* path);
 };
 
 LittleFSImpl::LittleFSImpl()
 {
 }
-
+/*
 bool LittleFSImpl::exists(const char* path)
 {
     File f = open(path, "r",false);
     return (f == true);
 }
-
+*/
 LittleFSFS::LittleFSFS() : FS(FSImplPtr(new LittleFSImpl())), partitionLabel_(NULL)
 {
 }