#732: Unable to load banner MOTD on Arista

[mirceaulinic]

This PR attempts to fix #732, however I am surprised that nobody noticed this
issue before, which makes me questions what changed when (and why)? Without this
patch, loading a multiline banner motd fails (at least with the configuration I
tried to load):

>>> config = '''banner motd
... !!aaaa
... EOF
... '''
>>> e.load_merge_candidate(config=config)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/napalm/eos/eos.py", line 245, in load_merge_candidate
    self._load_config(filename, config, False)
  File "/usr/local/lib/python2.7/dist-packages/napalm/eos/eos.py", line 225, in _load_config
    commands = self._multiline_convert(commands, start=start, depth=depth)
  File "/usr/local/lib/python2.7/dist-packages/napalm/eos/eos.py", line 157, in _multiline_convert
    ret[s] = {'cmd': ret[s], 'input': "\n".join(ret[s+1:e])}
TypeError: sequence item 0: expected string or Unicode, dict found

[coveralls]

Coverage remained the same at ?% when pulling 8ca6707 on fix-732 into 38b0132 on develop.

[mirceaulinic]

As discussed with @bewing in private, and as per #732 (comment), this is not the right fix (actually there's no fix, as my syntax was incorrect).