QPID-4733: Fix cmake installation of init scripts

- Install both qpidd and qpidd-primary init scripts.
- Fix path substitution to use absolute paths.
- Fix substitution to work on cmake and automake.
- Set executable permissions for init scripts.
- Do init script install on Unix only.

git-svn-id: https://svn.apache.org/repos/asf/qpid/branches/0.22@1469050 13f79535-47bb-0310-9956-ffa450edef68