Iterate over the file object

Since the file is being iterated over already, calling readlines() is
unnecessary. It also increases memory usage by reading the file into memory
and then iterating over that.

lib/ansible/modules/user.py

@@ -3140,7 +3140,7 @@ class BusyBox(User):
             with open("/etc/shells", "r") as f:
                 shells = [
                     shell
-                    for shell in (line.strip() for line in f.readlines())
+                    for shell in (line.strip() for line in f)
                     if shell
                     and not shell.startswith("#")
                 ]