There are two problems with obtaining the proxy status via the normal
proxy endpoint...
1. when TLS is enabled, this requires using TLS at the client end
2. the status URL is mixed in with the docker remote API, which is
rather unclean
There is limited value to having some status output from the proxy,
since all the output is constant.
So instead we log the version and command line args, and in `weave
status` only report whether the proxy is running.
We still want a way to wait for the proxy to start up, and log a nice
error if it dies. We do this by polling the docker logs for a startup
message.
Fixes#877. Fixes#876.
Undoes most of #756, #800, #854.
Caveats:
* TLS files must be present on the target server (and readable)
* TLS file paths cannot contain spaces
* TLS file paths must be absolute (i.e. cannot be relative)
* Bash argument parsing is terrible
Due to https://github.com/docker/docker/issues/9098, there is no way to
signal an exec. Instead we'll have to just poll the interface and hope.
Adds `weavewait -s` which is the way to tell weavewait to skip waiting
for a signal, which we use on execs
Matthias Radestock