DeprecationWarning: 'U' mode is deprecated

[nskalis]

Hi,

In Python3 the following is deprecated. This is causing pyez to give warnings when running in any CI environment.

/usr/lib/python3.6/site-packages/jnpr/junos/utils/config.py:501: DeprecationWarning: 'U' mode is deprecated
  rpc_contents = open(kvargs['path'], 'rU').read()

[stacywsmith]

Suggest replacing current /usr/lib/python3.6/site-packages/jnpr/junos/utils/config.py:501:

    rpc_contents = open(kvargs['path'], 'rU').read()

with:

    try:
        # Explicitly request Python 3.x universal newline 
        rpc_contents = open(kvargs['path'], 'r', newline=None).read()
    except TypeError:
        # Fallback to Python 2.x universal newline 
        rpc_contents = open(kvargs['path'], 'rU').read()

See this question and answer.