Adds a GPL warning to the binary installer

Also remove some bashism to fix #1456.

--
Change-Id: I374f1290a3eb9e9e5bcc48e19a1c0ab1c5bdaa99
Reviewed-on: https://bazel-review.googlesource.com/#/c/3952/
MOS_MIGRATED_REVID=126572632

scripts/packages/template_bin.sh

diff --git a/scripts/packages/template_bin.sh b/scripts/packages/template_bin.sh
index 3ae4ed2..5323946 100755
--- a/scripts/packages/template_bin.sh
+++ b/scripts/packages/template_bin.sh
@@ -26,11 +26,16 @@
 echo "Bazel installer"
 echo "---------------"
 echo
+echo "Bazel is bundled with software licensed under the GPLv2 with Classpath exception."
+echo "You can find the sources next to the installer on our release page:"
+echo "   https://github.com/bazelbuild/bazel/releases"
+echo
+
 cat <<'EOF'
 %release_info%
 EOF
 
-function usage() {
+usage() {
   echo "Usage: $progname [options]" >&2
   echo "Options are:" >&2
   echo "  --prefix=/some/path set the prefix path (default=/usr/local)." >&2
@@ -73,7 +78,7 @@
 bin="${bin//%prefix%/${prefix}}"
 base="${base//%prefix%/${prefix}}"
 
-function test_write() {
+test_write() {
   local file="$1"
   while [ "$file" != "/" ] && [ -n "${file}" ] && [ ! -e "$file" ]; do
     file="$(dirname "${file}")"