remote: Fix redirect option spelling and boolean flags

remote-add registers --no-follow_redirect instead of the documented
--no-follow-redirect. Its reversed flag and both remote-modify redirect
flags set initially false booleans to false, so the policy is not applied.

Correct the option spelling and remove G_OPTION_FLAG_REVERSE so these
switches enable the corresponding configuration updates.
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f