As with the previous similar changes, this is intended to catch
problems as they happen instead of ignoring them and continuing on
to potentially fail later. Setting this on all existing scripts
will allow us to enforce use via Jenkins.
Change-Id: Iad2d490c86dceab148ea9ab08f457c49a5d5352e
The pypi element is cool, but some folk have local network mirrors
which we should permit them to use.
Change-Id: Ie840ad1184e72b0e01966eee0298cfd6511b6c19
Just adding an element shouldn't make a disk image build crash, even if
we're not using the element for its intended purpose.
Change-Id: I2ec91ce4975b3b0deee7c85bb223f854c694553f
Using a custom pypi mirror can be very convenient, making image builds
substantially faster - because we create multiple virtual
environments we benefit more than single-virtualenv users would.
Change-Id: I997daf1f9477c447e1fb30818aea9e80a49b31a6
