snapshot: Deal with no patches field
snapshot: Deal with no patches field

Without this, it will create an undefined component which will
confuse everything iterating over the components list.

chergert/gnome-continuous,GNOME/gnome-ostree,GNOME/gnome-ostree,chergert/gnome-continuous,chergert/gnome-continuous,vrutkovs/vrutkovs.github.io,vrutkovs/vrutkovs.github.io,vrutkovs/vrutkovs.github.io,GNOME/gnome-ostree