posix: stat() uses errno, not its return value, for errors
posix: stat() uses errno, not its return value, for errors

l/stat() always return -1 on error, so we must examine errno if we
want to handle errors specially.  (This is only used for judging whether
to print an error message, so it's not too harmful.)

TEST=symlink to nowhere in a dir; Chrome should not complain about
that symlink when enumerating files in the directory

Review URL: http://codereview.chromium.org/1352001

git-svn-id: http://src.chromium.org/svn/trunk/src@42647 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 4d58b2c1203033f1f81af89073e36aa7bcab114a
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser