Revert "Improved support for projects located on Windows network drives // Issue #3417"

This reverts commit a0c959be28.

platformio/project/integration/generator.py

@@ -134,7 +134,7 @@ class ProjectGenerator:
             for root, _, files in os.walk(self.config.get("platformio", "src_dir")):
                 for f in files:
                     result.append(
-                        os.path.relpath(os.path.join(os.path.abspath(root), f))
+                        os.path.relpath(os.path.join(os.path.realpath(root), f))
                     )
         return result