cmd/golsp: make each log message result from a single call to fmt.Fprintf
cmd/golsp: make each log message result from a single call to fmt.Fprintf

If several RPCs finish together the existing code may mix the log
messages, making reading them difficult.

Change-Id: I1de15373f739c97ccfaf210511b5f5443f7ef036
Reviewed-on: https://go-review.googlesource.com/c/154346
Reviewed-by: Rebecca Stambler <d7cf11e5f299d88ea8348366a9fc4f7c335c3afa@golang.org>

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