remote: add camel-cased *.tagOpt key, like clone

Change "git remote add" so that it adds a *.tagOpt key, and not the lower-cased *.tagopt on "git remote add --no-tags", just as "git clone --no-tags" would do. This doesn't matter for anything that reads the config. It's just prettier if we write config keys in their documented camelCase form to user-readable config files. When I added support for "clone -no-tags" in 0dab2468ee5 (clone: add a --no-tags option to clone without tags, 2017-04-26) I made it use the *.tagOpt form, but the older "git remote add" added in 111fb858654 (remote add: add a --[no-]tags option, 2010-04-20) has been using *.tagopt all this time. It's easy enough to add a test for this, so let's do that. We can't use "git config -l" there, because it'll normalize the keys to their lower-cased form. Let's add the test for "git clone" too for good measure, not just to the "git remote" codepath we're fixing. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>