cmd/guru: emacs: add go-guru-debug variable
cmd/guru: emacs: add go-guru-debug variable

Don't print debug messages unless go-guru-debug is set.

Change-Id: I1332a0b10eba1d1107ef987734b2b787ae28d9c2
Reviewed-on: https://go-review.googlesource.com/20432
Reviewed-by: Alan Donovan <7069e9552f9d110b0a0f326b96f22f63fb99dfc1@google.com>

golang/tools,syreclabs/go-tools,syreclabs/go-tools,syreclabs/go-tools,golang/tools,golang/tools,golang/tools,golang/tools,syreclabs/go-tools,syreclabs/go-tools,syreclabs/go-tools