Fix crypttab (#3121)

* Fix error in crypttab doc

* Use path type for file argument

This permit to make sure that $HOME and '~' are properly
expanded, even if in the case of crypttab, this might not make
a lot of sense

lib/ansible/modules/extras/system/crypttab.py

@@ -52,7 +52,7 @@ options:
     default: null
   password:
     description:
-      - Encryption password, the path to a file containing the pasword, or
+      - Encryption password, the path to a file containing the password, or
         'none' or '-' if the password should be entered at boot.
     required: false
     default: "none"
@@ -92,9 +92,9 @@ def main():
             name           = dict(required=True),
             state          = dict(required=True, choices=['present', 'absent', 'opts_present', 'opts_absent']),
             backing_device = dict(default=None),
-            password       = dict(default=None),
+            password       = dict(default=None, type='path'),
             opts           = dict(default=None),
-            path           = dict(default='/etc/crypttab')
+            path           = dict(default='/etc/crypttab', type='path')
         ),
         supports_check_mode = True
     )