Update message when auto installation is disabled

[Nmishin]

Related to #172

tenv: 2.1.8

The message:

$ tenv tf list  
  1.2.7
  1.3.7
  1.5.5
  1.5.7
* 1.8.0 (set by /Users/nmishin/.tenv/Terraform/version)
  1.8.5
$ tenv tf use 1.2.0
Auto-install is disabled. To install 1.2.0 version you can set environment variable TENV_AUTO_INSTALL=true, or install it via any of the following command: 'tenv terraform install', 'tenv terraform install 1.2.0'
Error: no compatible version found locally
$ tenv terraform install
Resolved version from /Users/nmishin/.tenv/Terraform/version : 1.8.0
Terraform 1.8.0 already installed

It looks like the behavior has changed a little bit, and the message is wrong now because tenv terraform use doesn't update the version file.