setup_gjf.sh: Add support for multiple version

We are in process of upgrading to new google-java-format version. To
simplify upgrade process, allow to set up multiple different versions
of gjf distribution.

To install currently used version 1.3 no parameter is needed

  $ tools/setup-gjf.sh

The resulting script has now version suffix:
  tools/format/google-java-format-1.3

To update to a newer version, version parameter can be passed now:

  $ tools/setup-gjf.sh 1.5

Note, that because of SHA1 check only supported versions can be
currently installed: 1.3 and 1.5.

Change-Id: Id2464cd88291f7f7376df98ca2a396e2458d07a4

tools/setup_gjf.sh

@@ -17,8 +17,20 @@
 set -eu
 
 # Keep this version in sync with dev-contributing.txt.
-VERSION="1.3"
-SHA1="a73cfe6f9af01bd6ff150c0b50c9d620400f784c"
+VERSION=${1:-1.3}
+
+case "$VERSION" in
+1.3)
+    SHA1="a73cfe6f9af01bd6ff150c0b50c9d620400f784c"
+    ;;
+1.5)
+    SHA1="b1f79e4d39a3c501f07c0ce7e8b03ac6964ed1f1"
+    ;;
+*)
+    echo "unknown google-java-format version: $VERSION"
+    exit 1
+    ;;
+esac
 
 root="$(git rev-parse --show-toplevel)"
 if [[ -z "$root" ]]; then
@@ -33,7 +45,7 @@ name="google-java-format-$VERSION-all-deps.jar"
 url="https://github.com/google/google-java-format/releases/download/google-java-format-$VERSION/$name"
 "$root/tools/download_file.py" -o "$dir/$name" -u "$url" -v "$SHA1"
 
-launcher="$dir/google-java-format"
+launcher="$dir/google-java-format-$VERSION"
 cat > "$launcher" <<EOF
 #!/bin/bash
 #