Fix project search if a directory is called manage.py, fixes #1314

jedi/_compatibility.py

@@ -365,6 +365,11 @@ try:
 except NameError:
     NotADirectoryError = IOError
 
+try:
+    IsADirectoryError = IsADirectoryError
+except NameError:
+    IsADirectoryError = IOError
+
 try:
     PermissionError = PermissionError
 except NameError: