Using incomplete cache key results in duplicate data when querying multiple basecurrencies.

[dan-da]

I found this problem in the course of investigating:
bisq-network/analytics#1 (comment)

A memory cache is used to store results temporarily during a request. The cache key was not including information about the basecurrency, thus the first result stored for a given key would be used even for other base currencies.

wrong code:

        static $results = null;
        $val = @$results[$key];
        if( $val ) {
            return $val;
        }

fixed code:

        static $results = null;
        $fullkey = $file . $key;
        $val = @$results[$fullkey];
        if( $val ) {
            return $val;
        }

[dan-da]

fixed in fd377e3

[dan-da]

related commits: 8dded19 and 64a002e