canonicalize-lgpl: reject non-directory with trailing slash This synchronizes glibc to gnulib. For gnulib to glibc, see: http://sources.redhat.com/bugzilla/show_bug.cgi?id=10635 * lib/canonicalize-lgpl.c (__realpath): Synchronize with glibc. * tests/test-canonicalize-lgpl.c (main): Enhance test. This catches failures in glibc 2.3.5. * tests/test-canonicalize.c (main): Likewise. Signed-off-by: Eric Blake <ebb9@byu.net>