STYLE: adjust tutorial Allclean scripts (issue #310)

- A few without a 'cd' at the start.
  Several remove files that are already covered by the cleanCase function.

tutorials/mesh/foamyHexMesh/blob/Allclean

@@ -1,12 +1,11 @@
 #!/bin/sh
 cd ${0%/*} || exit 1    # Run from this directory
 
-# Source tutorial run functions
+# Source tutorial clean functions
 . $WM_PROJECT_DIR/bin/tools/CleanFunctions
 
 cleanCase
-
-rm -rf 0 > /dev/null 2>&1
+rm -rf 0
 
 rm -rf constant/triSurface/blob.stl.gz > /dev/null 2>&1
 
@@ -23,5 +22,4 @@ rm -rf constant/backgroundMeshDecomposition/polyMesh/points > /dev/null 2>&1
 rm -rf snapToSurface?.obj > /dev/null 2>&1
 rm -rf tetsToSnapTo.obj > /dev/null 2>&1
 
-
 #------------------------------------------------------------------------------