Fix processutils.execute errors on windows

Added a check for existence of geteuid.

This fix is related to oslo-incubator commit:
d6a963e911b8456c06dceb5ee3cc88a70c08bf82

Fixes bug #1209410

Change-Id: Idd716a2104ba3fa24610825ce4bf9c8e2c6d490b
Merge "Fix processutils.execute errors on windows"