xbps-dgraph: only add revdeps when it's necessary.
xbps-dgraph: only add revdeps when it's necessary.

datenwolf/xbps,ebfe/xbps,stpx/xbps,stpx/xbps,ebfe/xbps,stpx/xbps,datenwolf/xbps,ebfe/xbps,datenwolf/xbps