largefiles: enable islfilesrepo() prior to a commit (issue3541) Previously, even if a file was added with --large, 'hg addremove' or 'hg ci -A' would add all files (including the previously added large files) as normal files. Only after a commit where a file was added with --large would subsequent adds or 'ci -A' take into account the minsize or the pattern configuration. This change more closely follows the help for largefiles, which mentions that 'add --large' is required to enable the configuration, but doesn't mention the previously required commit. Also, if 'hg add --large' was performed and then 'hg forget <file>' (both before a largefile enabling commit), the forget command would error out saying '.hglf/<file> not tracked'. This is also fixed. This reports that a repo is largefiles enabled as soon as a file is added with --large, which enables 'add', 'addremove' and 'ci -A' to honor the config settings before the first commit. Note that prior to the next commit, if all largefiles are forgotten, the repository goes back to reporting the repo as not largefiles enabled. It makes no sense to handle this by adding a --large option to 'addremove', because then it would also be needed for 'commit', but only when '-A' is specified. While this gets around the awkwardness of having to add a largefile, then commit it, and then addremove the other files when importing an existing codebase (and preserving that extra commit in permanent history), it does still require finding and manually adding one of the files as --large. Therefore it is probably desirable to have a --large option for init as well.