[telemetry] Fix support for older versions of psutil
[telemetry] Fix support for older versions of psutil

This patch modifies the code for listing leaked processes in Telemetry
to work on old versions of psutil.

The psutil API changed quite a lot in version 2.0. The issue fixed by
this patch is that Process.name changed from a property to a method
(http://grodola.blogspot.com/2014/01/psutil-20-porting.html):

  p = psutil.Process()
  print p.name    # psutil < 2.0
  print p.name()  # psutil >= 2.0

Review URL: https://codereview.chromium.org/1384553005

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#352638}

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