mirror.starlingx.cengn.ca no longer exists. CENGN is kindly forwarding
requests to the new location mirror.starlingx.windriver.com for now, but
that will only last a few months. We need to replace all the references
with the new URL.
I will also remove as many 'cengn' references as possible, replacing
them with 'stx_mirror'
TESTS
=====
Run "stx config --upgrade" with various combinations of the old,
new & missing values.
Run "./stx-init-env --rebuild" and verify stx-localrc is updated
as well.
Partial-Bug: 2033555
Signed-off-by: Scott Little <scott.little@windriver.com>
Change-Id: I18491fb5aa0087029d51bb35c236613c1dc092bc
2684e9e3fd