Delete batch files from deb (and rpm) packages

I noticed on my Linux system, when using the package that it is also installing .bat files (for Windows) along with the bash scripts to run the script.

Here is a patch that should take care of removing them before building the package (untested):

```
diff --git a/pkg/build.sh b/pkg/build.sh
index 8ad876b..0d56ab4 100755
--- a/pkg/build.sh
+++ b/pkg/build.sh
@@ -41,6 +41,9 @@ fi

tar -C $destdir/$prefix --strip-components 1 -zxpf $tar

+# Delete batch files
+rm -f $destdir/opt/logstash/bin/*.bat
+
case $os@$release in
centos@*|fedora@*|el6@*|sl6@*)
mkdir -p $destdir/etc/logrotate.d
```