fu-tool: fix a regression where activate stopped working in c7d870aa9
fu-tool: fix a regression where activate stopped working in c7d870aa9

Activate was no longer calling coldplug meaning even if devices were
in the pending database they wouldn't activate.

hughsie/fwupd,hughsie/fwupd,fwupd/fwupd,hughsie/fwupd,fwupd/fwupd,hughsie/fwupd,fwupd/fwupd,fwupd/fwupd