Remove the previous coreutils-5.0 source directory

coreutils-5.0 is built twice in the same source directory during the
bootstrap. This can create some unexpected issues.

sysa/coreutils-5.0/coreutils-5.0.sh

@@ -4,6 +4,10 @@
 
 src_unpack() {
     src_dir="${base_dir}/src"
+
+    # Remove previous source diretory
+    rm -rf "${pkg}"
+
     tar -xf "${src_dir}/${pkg}.tar"
 }