tox: Fix warnings reported by PyLint
tox: Fix warnings reported by PyLint

fritzcollectd.py:27: [C0411(wrong-import-order), ]
    third party import "import fritzconnection" should be placed before
    "import collectd"
fritzcollectd.py:29: [C0411(wrong-import-order), ]
    third party import "from lxml.etree import XMLSyntaxError" should
    be placed before "import collectd"

fetzerch/fritzcollectd