remove uuid dependency

[qiwzhang]

it looks that mixerclient added a dependency on libuuid from
e2fsprogs, which isn't part of base OS (i.e. Goobuntu doesn't have it
installed by default).

However, this dependency wasn't added via Bazel, so the build is
broken and not hermetic at all.

I wanted to make a PR adding libuuid, but it looks that it's licensed
under GPLv2, which means that we cannot statically link against it,
AFAIK.

I think it is from util-linux, yes it is still LGPL, so I think we should remove the dependency.

Envoy has its own uuid impl:
https://github.com/lyft/envoy/blob/master/source/common/runtime/runtime_impl.cc#L28