git diff --quiet exits with 1 on clean tree with CRLF conversions

If "git diff --quiet" finds it necessary to compare actual file contents, and a file requires CRLF conversion, then it incorrectly exits with an exit code of 1 even if there have been no changes.

The patch below adds a test file that shows the problem.

The first test of diff without --quiet correctly has an exit status of zero on both invocations.

The second test of diff with --quiet has an exit code of zero on the first invocation, but an exit code of one on the second invocation. Further invocations (not included in the test) may yield an exit code of 1. Calling "git status" always fixes things.

(The touching with "tomorrow" was my attempt to avoid the sleep, but that didn't seem to help - it appears that time must pass in order to ensure that the cache is not used.)

The culprit would appear to be in diff_filespec_check_stat_unmatch where it assumes that the files are different if their sizes are different:

	if (!DIFF_FILE_VALID(p->one) || /* (1) */
	    !DIFF_FILE_VALID(p->two) ||
	    (p->one->oid_valid && p->two->oid_valid) ||
	    (p->one->mode != p->two->mode) ||
	    diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
	    diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
	    (p->one->size != p->two->size) ||
	    !diff_filespec_is_identical(p->one, p->two)) /* (2) */
		p->skip_stat_unmatch_result = 1;

In the failing case p->one->size == 14 and p->two->size == 12.

Mike.