Workaround for a wrong bundle index

This is work in progress, the reason why the situation arise has not yet been found and there are likely other ways in which the index can be wrong/stale (based on user reports like issue #998).

Frameworks/BundlesManager/src/fs_cache.cc

@@ -131,6 +131,12 @@ namespace fs
 
 	plist::dictionary_t cache_t::content (std::string const& path)
 	{
+		auto it = _cache.find(path);
+		if(it != _cache.end() && it->second.type() == entry_type_t::missing)
+		{
+			fprintf(stderr, "content requested for missing item: ‘%s’\n", path.c_str());
+			_cache.erase(it);
+		}
 		return resolved(path).content();
 	}