Usual update to latest gnulib status.  In particular this update
fixes at least one issue that can be seen in libvirt, by silencing
a valgrind detection of uninitialized memory:
https://bugzilla.redhat.com/show_bug.cgi?id=1174147

* .gnulib: Update to latest.
* bootstrap: Resync to gnulib.
Signed-off-by: NEric Blake <eblake@redhat.com>