TBR: devtools: update godepcop file to allow imports from jiri/lib.
TBR: devtools: update godepcop file to allow imports from jiri/lib.

PresubmitTest: none
Change-Id: Ia0beba73dfcb7000b84b73fbc9660d9efa4c32af

vanadium/go.devtools,vanadium/go.devtools,vanadium/go.devtools