Truncate FAT filesystem label until 1st occurance of a blank (0x20)

According to spec the FAT filesystem label is not terminated by a
\0-byte but instead has a fixed length where the name is padded by
blanks.
Before libblkid-tiny just passed the always 11 bytes long blank padded
string through, however it makes matching for a filesystem label
inconsistent with other filesystems, which use a \0-terminated string.

Before: "foobar     "
After : "foobar"

Signed-off-by: Mirko Vogt <mirko-openwrt@nanl.de>

libblkid-tiny/vfat.c

@@ -422,8 +422,10 @@ static int probe_vfat(blkid_probe pr, const struct blkid_idmag *mag)
 	if (boot_label && memcmp(boot_label, no_name, 11))
 		blkid_probe_set_id_label(pr, "LABEL_FATBOOT", (unsigned char *) boot_label, 11);
 
-	if (vol_label)
-		blkid_probe_set_label(pr, (unsigned char *) vol_label, 11);
+	if (vol_label) {
+                strtok((char *) vol_label, " ");
+                blkid_probe_set_label(pr, (unsigned char *) vol_label, 11);
+        }
 
 	/* We can't just print them as %04X, because they are unaligned */
 	if (vol_serno)