[Bug]: fvm switch fails on some systems with running local cluster

[digikata]

What happened
fvm switch in a docker container failed with "Error: Text file busy (os error 26)"

Expected behavior
fvm switch or fvm update successfully switches versions

Describe the setup
Running fluvio and fvm switch on some os environments with a running cluster can lead to this error.

• Macos: this behavior does not occur
• docker: this bug occurs
• linux: this bug can occur

How to reproduce it (as minimally and precisely as possible)

1. Install fvm & fluvio
2. fvm install latest
3. fluvio cluster start Starts a local cluster
4. fvm switch stable
   Causes an "Error: Text file busy (os error 26)"

Additional context
A workaround is to shut down the local fluvio cluster, switch versions, then restart. On switch for linux environments, the binaries may need to be unlinked before copying new binaries of the switch-to version.

An intermediate fix is to detect running instances and ask them to shutdown, but this is likely more complex than doing an unlnk.

[digikata]

Dockerfile for refernce:

FROM ubuntu:20.04

ENV TERM linux
ENV DEBIAN_FRONTEND noninteractive

RUN apt-get update
RUN apt-get install -y curl unzip

WORKDIR /fluvio

RUN curl -fsS https://hub.infinyon.cloud/install/install.sh | bash
RUN echo 'source "${HOME}/.fvm/env"' >> ~/.bashrc

CMD ["/bin/bash"]

## Instruction
##
## >> Build and Run Dockerfile
## docker build --tag fluvio .
## docker run --name fluvio -d fluvio sleep infinity
##
## >> Login into the container
## docker exec -ti fluvio bash 

[github-actions]

Stale issue message

[digikata]

For linux, probably need to std:fs::remove_file to cause an unlink first on binaries in the .flvuio/bin directory, then copy new versions in.

see https://stackoverflow.com/questions/16764946/what-generates-the-text-file-busy-message-in-unix

[digikata]

Fix tested and worked on Linux and within a linux docker env.