shim: Don't shadow err return in createPod
shim: Don't shadow err return in createPod

Correctly uses a named return value on createPod. Previously if err was
redeclared in a nested scope and then returned, defers would not see the
returned error value. In particular this prevented the UVM cleanup defer
from working properly.

Signed-off-by: Kevin Parsons <179e5f33d278e7f4e6411489dacfa9a734384f98@microsoft.com>

Microsoft/hcsshim