vsock: connect: avoid issues with modified script

When an in progress Bash script is modified, Bash will continue at the
character where it was before, generally causing troubles.

Because multiple --vsock-connect can be used for the same VM, it sounds
good to use a simple workaround of using a function to avoid such
issues.

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

virtme/commands/run.py

@@ -887,10 +887,13 @@ def do_it() -> int:
         with open(vsock_script_path, 'w', encoding="utf-8") as file:
             print((
                 '#! /bin/bash\n'
+                'main() {\n'
                 f'stty rows {rows} cols {cols} iutf8 echo\n'
                 'HOME=$(getent passwd ${virtme_user:-root} | cut -d: -f6)\n'
                 'cd ${virtme_chdir:+"${virtme_chdir}"}\n'
-                f'exec {cmd}'
+                f'exec {cmd}\n'
+                '}\n'
+                'main'  # use a function to avoid issues when the script is modified
             ), file=file)
         os.chmod(vsock_script_path, 0o755)