internal/lsp: handle results from setting options in initialize
internal/lsp: handle results from setting options in initialize

gopls configuration can come in through initializeOptions or through
the workspace/configuration request. Make sure to handle error results
in both cases.

Change-Id: Iaf33d23aa33381ce86803f5e8d090deb369b7341
Reviewed-on: https://go-review.googlesource.com/c/tools/+/227033
Run-TryBot: Rebecca Stambler <d7cf11e5f299d88ea8348366a9fc4f7c335c3afa@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Heschi Kreinick <e89ab2b172855aa0ad01c40c4d8a3535a61ac68a@google.com>

golang/tools,golang/tools,golang/tools,golang/tools,golang/tools