libxbps: xbps_repository_sync_index: return proper return value in error path.
libxbps: xbps_repository_sync_index: return proper return value in error path.

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