Delete src/tools/grit/LICENSE.
Delete src/tools/grit/LICENSE.

It's identicaly to src/LICENSE, so now that grit is in Chromium's repo,
this file is no longer needed.  (And other subdirectories we mirror out
don't have redundant LICENSE files either.)

BUG=553682

Review URL: https://codereview.chromium.org/1443123003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#359657}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk