Clean up obsolete and useless values of runtime dependencies
Some blueprints still set some runtimeDependencies to 'default'
or "default"
which is obsolete since more than 4 years.
Some other blueprints set some runtimeDependencies to "master"
which is pretty useless as far as I can tell. See
commit log message.
After this only two occurrences of runtimeDependencies with non-None
value (they set actual version numbers) remain.