tools/kvm_stat: use a more pythonic way to iterate over dictionaries

tools/kvm_stat: use a more pythonic way to iterate over dictionaries

BugLink: http://bugs.launchpad.net/bugs/1734130
If it's clear that the values of a dictionary will be used then use
the '.items()' method.

Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Tested-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
[Include fix for logging mode by Stefan Raspl]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 0eb578009a1d530a11846d7c4733a5db04730884)
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>