codestyle: Address issue related to C0411
codestyle: Address issue related to C0411

I doscovered this problem on an upgraded machine. For some reason this
problem was not found before with pylint 2.6.0.

This patch addresses the following issue detected by pylint

************ Module keylime.revocation_notifier
keylime/revocation_notifier.py:15:0: C0411: third party import "import simplejson as json" should be placed before "import zmq" (wrong-import-order)

Signed-off-by: Stefan Berger <5c96973112e540fb909b13997fcd087e5bfbee96@linux.ibm.com>

mit-ll/python-keylime,mit-ll/python-keylime,mit-ll/python-keylime,mit-ll/python-keylime