public String underVespaHome(String path) {
        if (path.startsWith("/")) return path;
        if (path.startsWith("./")) return path;
        return vespaHome() + "/" + path;
    }
Returns an absolute path produced by prepending vespaHome to the argument if it is relative.
If the path starts by "/" (absolute) or "./" (explicitly relative - useful for tests),
it is returned as-is.

@param path the path to prepend vespaHome to unless it is absolute
@return the given path string with the root path given from
        vespaHome() prepended, unless the given path is absolute, in which
        case it is be returned as-is
defaults/src/main/java/com/yahoo/vespa/defaults/Defaults.java