fix(instances): no deprecated crypt module from Python 3.11

The root password hash for a shut-off VM used crypt_r where installed
(Python 3.13) and fell back to the stdlib crypt, which Python 3.11 and
3.12 deprecate: `python -W error::DeprecationWarning manage.py check`
failed there. crypt-r (the same module, it requires Python 3.11) is now
installed from 3.11, and the module is chosen by the Python version;
3.10's crypt is not deprecated.

conf/requirements.txt

@@ -23,4 +23,4 @@ python-socketio==5.18.1
 segno==1.6.6
 websockify==0.13.0
 whitenoise==6.12.0
-crypt-r>=3.13.0; python_version >= "3.13"
+crypt-r>=3.13.0; python_version >= "3.11"

instances/views.py

@@ -1,7 +1,3 @@
-try:
-    import crypt_r as crypt
-except ImportError:
-    import crypt
 import difflib
 import functools
 import hashlib
@@ -11,10 +7,17 @@ import os
 import re
 import secrets
 import socket
+import sys
 import subprocess
 import time
 from ipaddress import ip_address
 
+# the stdlib crypt is deprecated from Python 3.11 and gone in 3.13: crypt_r is the same module
+if sys.version_info >= (3, 11):
+    import crypt_r as crypt
+else:
+    import crypt
+
 from accounts.models import UserInstance, UserSSHKey
 from admin.decorators import superuser_only
 from appsettings.models import AppSettings