`init_write_environment` - doesn't handle env vars with single tick quotes

[av]

The init_write_environment function from init routine fails to create a source-able file in case the $@ contains some env vars with single tick quote character: '

This results in environment.sh not being populated and then all kinds of things going wrong during the startup

Discovered the painful way, haha

[robballantyne]

Oh dear!

I'll take a look at that as soon as I can, thanks for the heads-up