Fix build-release.sh script to automatically get composer if not present.
Fix build-release.sh script to automatically get composer if not present.

tectronics/simplesamlphp,vivekrajenderan/simplesamlphp,vivekrajenderan/simplesamlphp,tectronics/simplesamlphp,vivekrajenderan/simplesamlphp,tectronics/simplesamlphp,vivekrajenderan/simplesamlphp,tectronics/simplesamlphp,tectronics/simplesamlphp,vivekrajenderan/simplesamlphp