Implement get_host_uptime for powervm driver

This patch implements the get_host_uptime method for the powervm driver
by calling the sysstat command on the backing hypervisor and returning
the parsed results.

Fixes bug 1191785

Change-Id: I67aaf6a5f5eb6b3a411ca9a0284d9a3016dd2947
remove locals() from virt/hyperv package

Also fix logging issue with missing local variable for
existing placeholder

fixes bug 1171936

Change-Id: I6e32364983372945c2b69bb92cd3a96689b7a53c
Merge "remove locals() from virt/hyperv package"
Merge "Implement get_host_uptime for powervm driver"