lib/package_unpack.c: fix a meamleak in error path.
lib/package_unpack.c: fix a meamleak in error path.

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