Fixed documentation and options to address new sanity tests

- https://docs.ansible.com/ansible/latest/dev_guide/testing_validate-modules.html

Signed-off-by: Hideki Saito <saito@fgrep.org>

plugins/modules/mount.py

@@ -50,7 +50,7 @@ options:
         with subsequent runs.
       - Has no effect on Solaris systems.
     type: str
-    default: 0
+    default: '0'
   passno:
     description:
       - Passno (see fstab(5)).
@@ -59,7 +59,7 @@ options:
         with subsequent runs.
       - Deprecated on Solaris systems.
     type: str
-    default: 0
+    default: '0'
   state:
     description:
       - If C(mounted), the device will be actively mounted and appropriately
@@ -667,12 +667,12 @@ def main():
     module = AnsibleModule(
         argument_spec=dict(
             boot=dict(type='bool', default=True),
-            dump=dict(type='str'),
+            dump=dict(type='str', default='0'),
             fstab=dict(type='str'),
             fstype=dict(type='str'),
             path=dict(type='path', required=True, aliases=['name']),
             opts=dict(type='str'),
-            passno=dict(type='str', no_log=False),
+            passno=dict(type='str', no_log=False, default='0'),
             src=dict(type='path'),
             backup=dict(type='bool', default=False),
             state=dict(type='str', required=True, choices=['absent', 'mounted', 'present', 'unmounted', 'remounted']),