Suppress flake8 warnings from the change in the parent commit

Author: felker

plasma/models/runner.py

@@ -12,7 +12,7 @@
 import sys
 import matplotlib
 matplotlib.use('Agg')
-import matplotlib.pyplot as plt
+import matplotlib.pyplot as plt  # noqa
 
 # if sys.version_info[0] < 3:
 #     from itertools import imap

plasma/utils/performance.py

@@ -7,8 +7,8 @@
 import os
 import matplotlib
 matplotlib.use('Agg')  # for machines that don't have a display
-import matplotlib.pyplot as plt
-from matplotlib import rc
+import matplotlib.pyplot as plt  # noqa
+from matplotlib import rc  # noqa
 rc('font', **{'family': 'serif', 'sans-serif': ['Times']})
 rc('text', usetex=True)