libxbps: make the vpkg_provider_and_revdeps_downgrade test case work.
libxbps: make the vpkg_provider_and_revdeps_downgrade test case work.

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