build/cmd/coordinator: fix typo in gce comments
build/cmd/coordinator: fix typo in gce comments

Change-Id: I439ba378d0b7ef6655366c8aa5268c22504fb219
Reviewed-on: https://go-review.googlesource.com/9931
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

evandbrown/build,evandbrown/build,golang/build,golang/build,proppy/build,evandbrown/build,proppy/build,golang/build,golang/build,proppy/build,proppy/build