df: Skip final '/' character when calculating basename.

Previously it was including the final '/' character when calculating
the basename for the -a option eg:

Filesystem                                Size       Used  Available  Use%
/Ubuntu1010x64:/dev/sda1                  9.4G       2.3G       6.6G   25%

With this patch the '/' is not printed.

1 files changed, 2 insertions, 0 deletions

diff --git a/df/main.c b/df/main.c
index 55e5eaa8..7ac5a6c1 100644
--- a/df/main.c
+++ b/df/main.c
@@ -281,6 +281,8 @@ main (int argc, char *argv[])
       name = strrchr (drvs->a.filename, '/');
       if (name == NULL)
         name = drvs->a.filename;
+      else
+        name++; /* skip '/' character */
       break;
     case drv_d:
       name = drvs->d.guest;