fix variants stats

Created by: alpianon

fix for #37 (closed)

.progress and .workload properties are calculated in AlienPackage constructor method.

from AlienPackage.js, line 60-onwards:

	constructor(data = {}) {
		if (data.id) this.id = data.id;
		if (data.tags) this.tags = data.tags;
		if (data.name) this.name = data.name;
		if (data.version) this.version = data.version;
		if (data.revision) this.revision = data.revision;
		if (data.variant) this.variant = data.variant;
		if (data.debian_matching) this.debian_matching = data.debian_matching;
		if (data.statistics) this.statistics = data.statistics;
		if (data.source_files) this.source_files = data.source_files;
		if (data.binary_packages) this.binary_packages = data.binary_packages;
		if (data.session_state) this.session_state = data.session_state
		if (data.cve_metadata && data.cve_metadata.result) {
			this.cve_metadata = data.cve_metadata
			this.collectCves();
		}

		var filestats = this.statistics.files;

		this.progress =
			filestats.audit_total == 0
				? 100
				: parseInt(
						(filestats.audit_done / filestats.audit_total) * 100
				  );
		this.workload = filestats.audit_done;
		this.workload_total = filestats.audit_total;
		this.match = this.debian_matching
			? (this.debian_matching.ip_matching_files /
					filestats.upstream_source_total) *
			  100
			: 0;

	}

However, when creating an AlienPackage without immediately setting .statistics.* properties, .progress and .workload are wrongly set, respectively, to 100% and 0. This happens when creating merged (i.e. with variants) packages, here (from Solda.vue, line 877 onwards):

        var merged_package = new AlienPackage({
          name: variants[a][0].name,
          version: variants[a][0].version,
          revision: variants[a][0].revision,
          variant: true,
          session_state: variants[a][0].session_state
        });

So a separate method has been created to do such calculation, that is called by the constructor method but can be separately called also after creating an object.