discontinued adhoc check (see also ea8343187225);

--- a/Admin/Release/CHECKLIST	Fri May 02 13:52:45 2014 +0200
+++ b/Admin/Release/CHECKLIST	Fri May 02 13:57:57 2014 +0200
@@ -17,7 +17,7 @@
 
 - check HTML header of library;
 
-- check ML sources: isabelle build -nal;
+- check sources: see isabelle.Check_Source;
 
 - run isabelle update_keywords;
 

--- a/src/Pure/Tools/build.scala	Fri May 02 13:52:45 2014 +0200
+++ b/src/Pure/Tools/build.scala	Fri May 02 13:57:57 2014 +0200
@@ -484,19 +484,8 @@
                 info.files.map(file => info.dir + file) :::
                 info.document_files.map(file => info.dir + file._1 + file._2)).map(_.expand)
 
-            if (list_files) {
+            if (list_files)
               progress.echo(cat_lines(all_files.map(_.implode).sorted.map("  " + _)))
-              for {
-                file <- all_files
-                if file.split_ext._2 == "ML"
-              } {
-                val path = info.dir + file
-                try { Symbol.decode_strict(File.read(path)) }
-                catch {
-                  case ERROR(msg) => cat_error(msg, "The error(s) above occurred in file " + path)
-                }
-              }
-            }
 
             val sources = all_files.map(p => (p, SHA1.digest(p.file)))