The git gui's recent repo list may become contaminated with duplicate
entries. The git gui would barf when attempting to remove one entry.
Remove them all - there is no option within 'git config' to selectively
remove one of the entries.
This issue was reported on the 'Git User' list
(https://groups.google.com/forum/#!topic/git-users/msev4KsQGFc,
Warning: gui.recentrepo has multiply values while executing).
And also by zosrothko as a Git-for-Windows issue
https://github.com/git-for-windows/git/issues/1014.
On startup the gui checks that entries in the recentrepo list are still
valid repos and deletes thoses that are not. If duplicate entries are
present the 'git config --unset' will barf and this prevents the gui
from starting.
Subsequent patches fix other parts of recentrepo logic used for syncing
internal lists with the external .gitconfig.
Reported-by: Alexey Astakhov <asstv7@gmail.com> Signed-off-by: Philip Oakley <philipoakley@iee.org>