libostree: update to 2018.3.
libostree: update to 2018.3.

Closes: #12777 [via git-merge-pr]

necrophcodr/void-packages,coredumb/void-packages,NeoChontrix/void-packages,necrophcodr/void-packages,coredumb/void-packages,coredumb/void-packages,NeoChontrix/void-packages,NeoChontrix/void-packages,NeoChontrix/void-packages,necrophcodr/void-packages,necrophcodr/void-packages,NeoChontrix/void-packages,necrophcodr/void-packages,NeoChontrix/void-packages,coredumb/void-packages,coredumb/void-packages,coredumb/void-packages