circleci-cli/install doesn't install the circleci tool

[CoRfr]

Orb version

0.1.9

What happened

The src/scripts/install.sh script simply doesn't install the CLI tool if it's missing.
It only does things if it already exists:

• either the installed version is the version we want, and it does nothing
• either it install a different version

But it expects the CLI tool to be already present, which seems wrong.

Expected behavior

If circleci is not available, I would expect it to install the tool with the provided version