Previously the proxy.go would directly call `os.Exit`. This patch
causes control to return to `main` where we can tear down any port
forward.
Signed-off-by: David Scott <dave.scott@docker.com>
Previously `execProxy` would
- create the proxy
- signal success/failure to the parent
- run forever (until signalled)
Since we want to add more proxy setup and teardown, this patch
removes the proxy creation from `execProxy` and renames it to
`proxyForever`. Later patches will be able to perform the necessary
side-effects before signalling success to the parent.
Signed-off-by: David Scott <dave.scott@docker.com>
