Add an autocmd to move the cursor to first line

This is for gitcommits, where I never want to open the file editing a
line down in the middle of the file.
Signed-off-by: Austin Beam <austinbeam@gmail.com>
ftplugin/gitcommit: Don't use cindent

This causes an indent in commit messages on a newline after a comma, and
is rather annoying :)