V8 Buildbot: Let auto-roller try to push new versions more frequently.
V8 Buildbot: Let auto-roller try to push new versions more frequently.

BUG=451975
TBR=tandrii@chromium.org

Review URL: https://codereview.chromium.org/885633002

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@293840 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build