[copyright] add MIT license headers to .sh scripts where missing

Years are set according to 'git log' history

Zcash: Only the scripts we have that are missing the header.

contrib/tidy_datadir.sh

@@ -1,4 +1,7 @@
 #!/bin/bash
+# Copyright (c) 2013 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 if [ -d "$1" ]; then
   cd "$1" || exit 1

test/lint/git-subtree-check.sh

@@ -1,4 +1,7 @@
 #!/bin/sh
+# Copyright (c) 2015 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 export LC_ALL=C
 DIR="$1"