Fix and create code-smell test for line endings.

test/sanity/code-smell/line-endings.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+grep -RIPl '\r' . 2>/dev/null \
+    --exclude-dir .git \
+    | grep -v -F \
+    -e './test/integration/targets/win_regmerge/templates/win_line_ending.j2'
+
+if [ $? -ne 1 ]; then
+    printf 'One or more file(s) listed above have invalid line endings.\n'
+    printf 'Make sure all files use "\\n" for line endings instead of "\\r\\n".\n'
+    exit 1
+fi