annex-checkuuid=false prevents the git config of a remote from being read.
So, the remoteGitConfig will be an empty config when that's set.

I've mostly removed uses of remoteGitConfig, but there are two in
Remote.Git, which are needed for annexDifferences.
So, `annex.tune.*` config the remote won't be honored when
annex-checkuuid=false.

The best thing would be to remove remoteGitConfig, to avoid such problems
in the future. --[[Joey]]

> [[done]] --[[Joey]]
