Replace file handling with context managers in files-modules and parsing vault. (#65371)

lib/ansible/modules/blockinfile.py

@@ -242,9 +242,8 @@ def main():
         original = None
         lines = []
     else:
-        f = open(path, 'rb')
-        original = f.read()
-        f.close()
+        with open(path, 'rb') as f:
+            original = f.read()
         lines = original.splitlines(True)
 
     diff = {'before': '',

lib/ansible/parsing/vault/__init__.py

@@ -398,9 +398,8 @@ class FileVaultSecret(VaultSecret):
 
         # TODO: replace with use of self.loader
         try:
-            f = open(filename, "rb")
-            vault_pass = f.read().strip()
-            f.close()
+            with open(filename, "rb") as f:
+                vault_pass = f.read().strip()
         except (OSError, IOError) as e:
             raise AnsibleError("Could not read vault password file %s: %s" % (filename, e))