Warning after a rebase

[jstolarek]

[111 of 120] Compiling Database.DSH.VSL.Vectorize ( src/Database/DSH/VSL/Vectorize.hs, dist/build/Database/DSH/VSL/Vectorize.o )

src/Database/DSH/VSL/Vectorize.hs:116:5: warning: [-Wincomplete-patterns]
    Pattern match(es) are non-exhaustive
    In a case alternative: Patterns not matched: (GroupAgg _)
    |
116 |     case f of
    |     ^^^^^^^^^..

Investigate & fix.