Fix two typos, "messsage" and "containg"

This patch set updated two wrong words:
+ In error.py file, it should be changed from "messsage" to "message"
+ In utils.py file, it should be changed from "containg" to "contaning"

Change-Id: I5ad121ec58ccc6e5f3cc499eca50d16e691f217e

ironic_python_agent/errors.py

@@ -70,7 +70,7 @@ class CommandExecutionError(RESTError):
 class InvalidCommandError(InvalidContentError):
     """Error which is raised when an unknown command is issued."""
 
-    messsage = 'Invalid command'
+    message = 'Invalid command'
 
     def __init__(self, details):
         super(InvalidCommandError, self).__init__(details)

ironic_python_agent/utils.py

@@ -361,7 +361,7 @@ def get_journalctl_output(lines=None, units=None):
 def gzip_and_b64encode(io_dict=None, file_list=None):
     """Gzip and base64 encode files and BytesIO buffers.
 
-    :param io_dict: A dictionary containg whose the keys are the file
+    :param io_dict: A dictionary containing whose the keys are the file
         names and the value a BytesIO object.
     :param file_list: A list of file path.
     :returns: A gzipped and base64 encoded string.