[BUG] SyntaxWarning: invalid escape sequence

[waldiTM]

Describe the bug: A clear and concise description of what the bug is.

Several parts throw SyntaxWarning. Someone even helpfully disabled the pylint warning for this problem.

All regular expressions must be creates as the correct string type: r"…".

azurelinuxagent/ga/env.py:40
  /build/source/azurelinuxagent/ga/env.py:40: SyntaxWarning: invalid escape sequence '\.'
    re.compile("^(.*)\.(\d+)\.(xml)$", re.IGNORECASE)  # pylint: disable=W1401

azurelinuxagent/agent.py:331
  /build/source/azurelinuxagent/agent.py:331: SyntaxWarning: invalid escape sequence '\w'
    m = re.match("^(?:[-/]*)configuration-path:([\w/\.\-_]+)", arg)  # pylint: disable=W1401