maint: update to latest gnulib

Among others, this fixes a cosmetic bug where bootstrap stated:

./bootstrap: Bootstrapping from checked-out http://libvirt.org sources...

instead of the intended:

./bootstrap: Bootstrapping from checked-out libvirt sources...

* .gnulib: Update to latest, for bootstrap improvement.
* bootstrap: Resync from gnulib.

.gnulib

@@ -1 +1 @@
-Subproject commit 92f3a4c8e52e64c233e260431d095dbf88554c14
+Subproject commit 0f8ddbf1a13a93a4584afdd82f0f87e498a0db6f

bootstrap

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Print a version string.
-scriptversion=2013-03-08.16; # UTC
+scriptversion=2013-05-08.20; # UTC
 
 # Bootstrap this package from checked-out sources.
 
@@ -140,20 +140,21 @@ po_download_command_format2=\
 "wget --mirror -nd -q -np -A.po -P '%s' \
  http://translationproject.org/latest/%s/"
 
+# Prefer a non-empty tarname (4th argument of AC_INIT if given), else
+# fall back to the package name (1st argument with munging)
 extract_package_name='
-  /^AC_INIT(/{
-     /.*,.*,.*, */{
+  /^AC_INIT(\[*/{
      s///
-       s/[][]//g
-       s/)$//
+     /^[^,]*,[^,]*,[^,]*,[ []*\([^][ ,)]\)/{
+       s//\1/
+       s/[],)].*//
        p
        q
      }
-     s/AC_INIT(\[*//
-     s/]*,.*//
+     s/[],)].*//
      s/^GNU //
      y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/
-     s/[^A-Za-z0-9_]/-/g
+     s/[^abcdefghijklmnopqrstuvwxyz0123456789_]/-/g
      p
   }
 '