Saltstack:salt execution module junos.rpc get-config invalid filter throws SyntaxError exception

[rsmekala]

Description of Issue/Question

No exception handling is implemented around XML parsing.

Logs:

➜ salt 'vmx' junos.rpc get-config format=xml dest=/tmp/cli.out filter='<configuration>' 

vmx:
    The minion function caused an exception: Traceback (most recent call last):
      File "/Users/rsmekala/PycharmProjects/salt/salt/minion.py", line 1660, in _thread_return
        return_data = minion_instance.executors[fname](opts, data, func, args, kwargs)
      File "/Users/rsmekala/PycharmProjects/salt/salt/executors/direct_call.py", line 12, in execute
        return func(*args, **kwargs)
      File "/Users/rsmekala/PycharmProjects/salt/salt/modules/junos.py", line 89, in wrapper
        conn.timeout = kwargs.pop('dev_timeout', None)
      File "/Users/rsmekala/PycharmProjects/salt/salt/modules/junos.py", line 215, in rpc
        else:
      File "src/lxml/etree.pyx", line 3190, in lxml.etree.XML
      File "src/lxml/parser.pxi", line 1877, in lxml.etree._parseMemoryDocument
      File "src/lxml/parser.pxi", line 1758, in lxml.etree._parseDoc
      File "src/lxml/parser.pxi", line 1068, in lxml.etree._BaseParser._parseUnicodeDoc
      File "src/lxml/parser.pxi", line 601, in lxml.etree._ParserContext._handleParseResultDoc
      File "src/lxml/parser.pxi", line 711, in lxml.etree._handleParseResult
      File "src/lxml/parser.pxi", line 640, in lxml.etree._raiseParseError
      File "<string>", line 1
    lxml.etree.XMLSyntaxError: Premature end of data in tag configuration line 1, line 1, column 16

[rsmekala]

Closed PR: 1428175