Workaround for installing GmsCore ( directly alerts 'not installed' )

[Danko]

@timmo

BUT are we sure the problem is signature? Because here they say the problem is about redirecting. (@Licaon_Kter is actually in this subject)

Today’s morning the problem was finally (I’m not sure) gone and update works — those redirection in microG repo was temporarily disabled, as main developer said.