resolveContextName() is used to find which context to use, based on the
available configuration options. Once resolved, the context name is
used to load the actual context, which will fail if the context doesn't
exist, so there's no need to produce an error at this stage; only
check priority of the configuration options to pick the context
with the highest priority.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2f5698511a