Fix lint error in parallel processing.
Fix lint error in parallel processing.

gyp.input fails the presubmit lint check because of an uninitialised global.
The last rewrite of the parallel processing CL eliminated the need for this to
be global, so just remove the global declaration.
Review URL: https://codereview.chromium.org/11026036

csulmone/gyp,csulmone/gyp,csulmone/gyp,csulmone/gyp