Account for the change in umount command in LFS

The command for unmounting the kernel vfs is now
  umount -Rv $LFS
So we have first to use that command in teardown (change in
kernfs.xsl). Second, since the command tries to umount
$LFS, but the Makefile is on $LFS, it fails. Ignore the
error in the Makefile (change in master.sh)

LFS/master.sh

@@ -299,7 +299,7 @@ build_Makefile() {           #
                 -e 's|\$\$LFS|$(MOUNT_PT)|g'`
   teardown=`cat ../kernfs-scripts/teardown.sh | \
             sed -e 's|^|	|'   \
-                -e 's|umount|sudo &|' \
+                -e 's|umount|-sudo &|' \
                 -e 's|\$LFS|$(MOUNT_PT)|'`
   teardownat=`cat ../kernfs-scripts/teardown.sh | \
               sed -e 's|^|	|'   \

common/kernfs.xsl

@@ -11,7 +11,8 @@
   <xsl:template match="/">
     <xsl:apply-templates select="//userinput[contains(string(),'--bind') or
                                              contains(string(),'/proc') or
-                                             contains(string(),'readlink')]"/>
+                                             contains(string(),'readlink') or
+                                             contains(string(),'-Rv')]"/>
   </xsl:template>
 
   <xsl:template match="userinput">