Expands path on file operations

Path might have to be expanded on some operations. It seems that path
containing '~' are not.
Using os.path.expanduser in appropriate places solves the problem, but
this might be required in many other places.

lib/ansible/module_common.py

@@ -262,6 +262,7 @@ class AnsibleModule(object):
         return context
 
     def user_and_group(self, filename):
+        filename = os.path.expanduser(filename)
         st = os.stat(filename)
         uid = st.st_uid
         gid = st.st_gid
@@ -338,6 +339,8 @@ class AnsibleModule(object):
         return changed
 
     def set_mode_if_different(self, path, mode, changed):
+        path = os.path.expanduser(path)
+
         if mode is None:
             return changed
         try: