Fix a bug with core_dir on Windows when it exists in the root of drive

Author: ivankravets

pioinstaller/core.py

@@ -39,15 +39,16 @@ def get_core_dir():
         return core_dir
 
     win_core_dir = os.path.splitdrive(core_dir)[0] + "\\.platformio"
-    if not os.path.isdir(win_core_dir):
-        try:
-            os.makedirs(win_core_dir)
-            with open(os.path.join(win_core_dir, "file.tmp"), "w") as fp:
-                fp.write("test")
-            os.remove(os.path.join(win_core_dir, "file.tmp"))
-            return win_core_dir
-        except:  # pylint:disable=bare-except
-            pass
+    if os.path.isdir(win_core_dir):
+        return win_core_dir
+    try:
+        os.makedirs(win_core_dir)
+        with open(os.path.join(win_core_dir, "file.tmp"), "w") as fp:
+            fp.write("test")
+        os.remove(os.path.join(win_core_dir, "file.tmp"))
+        return win_core_dir
+    except:  # pylint:disable=bare-except
+        pass
 
     return core_dir