Merge branch 'jc/diff-populate-filespec-size-only-fix' into maint

"git diff --quiet" relies on the size field in diff_filespec to be correctly populated, but diff_populate_filespec() helper function made an incorrect short-cut when asked only to populate the size field for paths that need to go through convert_to_git() (e.g. CRLF conversion). * jc/diff-populate-filespec-size-only-fix: diff: do not short-cut CHECK_SIZE_ONLY check in diff_populate_filespec()