Avoid crash in I/O Benchmark with small disks

.bin/Scripts/functions/io_graph.py

@@ -13,6 +13,9 @@ from functions.common import *
 def export_io_graph(disk):
   """Exports PNG graph using gnuplot, returns file path as str."""
   read_rates = disk.tests['I/O Benchmark'].read_rates
+  if not read_rates:
+    # No data, aborting
+    raise GenericError
   max_rate = max(read_rates) / (1024**2)
   max_rate = max(800, max_rate)
   out_path = '{}/iobenchmark-{}.png'.format(

.bin/Scripts/functions/osticket.py

@@ -196,6 +196,9 @@ class osTicket():
         # Create PNG graph
         try:
           graph_file = export_io_graph(dev)
+        except GenericError:
+          # No data to build graph, ignoring
+          pass
         except (AttributeError, KeyError):
           report.append('Failed to export graph')
         else: