Improve portability

- Fix shebang: `bash` is not always in `/bin/`, and since the script
  does not have bashism, rely on `sh` which is always in `/bin/`;
- Use `/opt/puppetlabs/puppet/bin/ruby` if this file exist and is
  executable, otherwise use `ruby` from $PATH;
- Use `code_manager_config_version.rb` if `.r10k-deploy.json` is found,
  and `config_version.rb` in all other cases.

scripts/config_version.sh

@@ -1,12 +1,14 @@
-#!/bin/bash
-if [ -e $1/$2/.r10k-deploy.json ]
-then
-  /opt/puppetlabs/puppet/bin/ruby $1/$2/scripts/code_manager_config_version.rb $1 $2
-elif [ -e /opt/puppetlabs/server/pe_version ]
-then
-  /opt/puppetlabs/puppet/bin/ruby $1/$2/scripts/config_version.rb $1 $2
-else
-  /usr/bin/git --version > /dev/null 2>&1 &&
-  /usr/bin/git --git-dir $1/$2/.git rev-parse HEAD ||
-  date +%s
+#!/bin/sh
+
+ruby=ruby
+script="$1/$2/scripts/config_version.rb"
+
+if [ -x /opt/puppetlabs/puppet/bin/ruby ]; then
+  ruby=/opt/puppetlabs/puppet/bin/ruby
 fi
+
+if [ -e $1/$2/.r10k-deploy.json ]; then
+  script="$1/$2/scripts/code_manager_config_version.rb"
+fi
+
+"${ruby}" "${script}" "$1" "$2"