devlib: Remove "future"

Remove the "future" dependency as devlib does not support Python 2
anymore.

Also remove the "from __future__ import division" as this is the default
in Python 3.

devlib/collector/dmesg.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 #
 
-from __future__ import division
 import re
 from itertools import takewhile
 from datetime import timedelta

devlib/collector/ftrace.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 #
 
-from __future__ import division
 import os
 import json
 import time