scripts/ceh-init.sh: To detect bzip2, use --help instead of --version.

bzip2 gets stuck on stdin when given --version from a script (as opposed to an
interactive terminal), this stalls ceh-init indefinitely. Using --help on bzip2
instead of --version solves the issue.
Merge pull request #6 from fredmorcos/master

scripts/ceh-init.sh: To detect bzip2, use --help instead of --version.