Remove remaining dependency of BLOCK on CONFIG modules.

- now, the BLOCK module dependends only on ERROR module; all other
   dependencies have been removed;

src/blocks.F90

@@ -143,8 +143,7 @@ module blocks
 !
   subroutine init_blocks()
 
-    use config, only : maxlev, ncells
-    use error , only : print_warning
+    use error, only : print_warning
 
     implicit none
 !

src/makefile

@@ -196,7 +196,7 @@ clean-all: clean-bak clean-data clean-exec clean-logs clean-modules            \
 
 #-------------------------------------------------------------------------------
 
-blocks.o        : blocks.F90 config.o error.o
+blocks.o        : blocks.F90 error.o
 boundaries.o    : boundaries.F90 blocks.o config.o error.o interpolation.o     \
                   mpitools.o variables.o timer.o
 config.o        : config.F90 error.o