Updates ion-functions submodule

Previous HEAD position was 8a8b432... Merge pull request #68 from
lukecampbell/loclrng-r2
HEAD is now at 8aae5b4... Merge pull request #69 from
lukecampbell/fillvals-r2
Merge pull request #1363 from lukecampbell/ion-funcs-r2

Updates submodules for ion-functions