get dxt_analyzer show arg working

darshan-util/dxt_analyzer.py

@@ -75,7 +75,7 @@ python dxt_analyzer.py -i darshan_dxt-v.txt
 
 import numpy as np
 import matplotlib
-matplotlib.use('PDF')
+#matplotlib.use('PDF')
 import matplotlib.pyplot as plt
 import re
 import argparse