[auto-roller] un-break the auto-roller

chromium/buildtools repo was moved and broke the V8 auto-roller.

This CL corrects the old-path.
Failed-Roll: https://chromium-review.googlesource.com/c/v8/v8/+/1459743

R=machenbach@chromium.org,sergiyb@chromium.org
CC=​yangguo@chromium.org

Bug: chromium:930050
Change-Id: I969c73c13bfa996b1010971c37d9325c22048c0a
Reviewed-on: https://chromium-review.googlesource.com/c/1460464
Commit-Queue: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59447}

DEPS

@@ -24,7 +24,7 @@ deps = {
   'v8/third_party/instrumented_libraries':
     Var('chromium_url') + '/chromium/src/third_party/instrumented_libraries.git' + '@' + 'a959e4f0cb643003f2d75d179cede449979e3e77',
   'v8/buildtools':
-    Var('chromium_url') + '/chromium/buildtools.git' + '@' + '6fbda1b24c1893a893b17aa219b765b9e7c801d8',
+    Var('chromium_url') + '/chromium/src/buildtools.git' + '@' + '106e9fce3799633f42b45ca8bbe9e84e1e23560',
   'v8/base/trace_event/common':
     Var('chromium_url') + '/chromium/src/base/trace_event/common.git' + '@' + 'e31a1706337ccb9a658b37d29a018c81695c6518',
   'v8/third_party/android_ndk': {