inotify: do not reuse watch descriptors

Prior to 2.6.31 inotify would not reuse watch descriptors until all of
them had been used at least once.  After the rewrite inotify would reuse
watch descriptors.  The selinux utility 'restorecond' was found to have
problems when watch descriptors were reused.  This patch reverts to the
pre inotify rewrite behavior to not reuse watch descriptors.

Signed-off-by: Eric Paris <eparis@redhat.com>