Make it explicit that the cryptography stubs are incomplete (#3331)

third_party/2and3/cryptography/__init__.pyi

@@ -0,0 +1,3 @@
+from typing import Any
+
+def __getattr__(name: str) -> Any: ...

third_party/2and3/cryptography/hazmat/__init__.pyi

@@ -0,0 +1,3 @@
+from typing import Any
+
+def __getattr__(name: str) -> Any: ...

third_party/2and3/cryptography/hazmat/primitives/__init__.pyi

@@ -0,0 +1,3 @@
+from typing import Any
+
+def __getattr__(name: str) -> Any: ...

third_party/2and3/cryptography/hazmat/primitives/asymmetric/__init__.pyi

@@ -0,0 +1,3 @@
+from typing import Any
+
+def __getattr__(name: str) -> Any: ...