[PATCH] build: update gnulib submodule to latest

[Pádraig Brady]

* gnulib: Sync recent cleanups and the fix for
missing df entries in the presence of bind mounts:
http://bugs.gnu.org/17833
* NEWS: Detail the df bug fix.
---
 NEWS   |    5 +++++
 gnulib |    2 +-
 2 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/NEWS b/NEWS
index 4e90b79..5a029f4 100644
--- a/NEWS
+++ b/NEWS
@@ -51,6 +51,11 @@ GNU coreutils NEWS                                    -*- 
outline -*-
   than error messages or values for the wrong file system.
   [These bugs were present in "the beginning".]
 
+  df now outputs all appropriate entries in the presence of bind mounts.
+  On some systems, entries would have been incorrectly elided due to
+  them being considered "dummy" mounts.
+  [bug introduced in coreutils-8.22]
+
   du now silently ignores directory cycles introduced with bind mounts.
   Previously it would issue a warning and exit with a failure status.
   [bug introduced in coreutils-8.1]
diff --git a/gnulib b/gnulib
index c6e14bb..648f4ae 160000
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit c6e14bbd5d404d147504acdd74c3fd17d5ef1088
+Subproject commit 648f4ae7311d1ad00658fc314e1a6c896f47e618
-- 
1.7.7.6