Panic when normalizing after summarizing

[shanson7]

Relevant Stack:

runtime error: invalid memory address or nil pointer dereference
/usr/lib/go/src/runtime/panic.go:82 (0x442fe0)
/usr/lib/go/src/runtime/signal_unix.go:390 (0x442e0f)
/metrictank/consolidation/consolidate.go:48 (0xa47f71)
/metrictank/expr/normalize.go:93 (0xbbfb9d)
/metrictank/expr/normalize.go:44 (0xbbf86a)
/metrictank/expr/func_divideserieslists.go:55 (0xba54b8)
/metrictank/expr/func_alias.go:28 (0xb99877)
/metrictank/expr/plan.go:309 (0xbc4f4b)
/metrictank/api/graphite.go:844 (0xc39d74)
/metrictank/api/graphite.go:268 (0xc32e8e)
...

I tracked this down to the use of summarize which drops the consolidator (effectively setting it to None. Consolidate then ends up using a nil aggFunc to try to consolidate which is no good.

At this point in processing, I don't think that None consolidator ever makes sense.

Edit: easy repro sum(summarize(A, '1min'),summarize(A, '2min'))