Generated bash completion scripts are set executable

[sgallagher]

Bash completion scripts should have permissions 0644, but they are generated by argbash as 0755 and have #!/usr/bin/bash at the top (notably, this includes the generated completion script for argbash itself).

This can actually cause problems for RPM packaging, as it will add a runtime dependency on /usr/bin/bash if it sees an executable script with such a hashbang in the %files payload.

Bash completion scripts are always loaded by the bash binary and serve no purpose when executed directly, so there really isn't any advantage to making them executable.