Make double-normalization harmless

This fixes a bug which is currently breaking recurring import, where
double-normalization causes source_enqueued_time to be encoded wrong.

Change-Id: Ice385c5d21b7015e4296498bf8a2ec52d1520f08
Merge branch 'master' into deployment

Change-Id: I103f844b578409b5c59b3a3348348e91c1b9aa62