Set num_events_max in Buildbot's WebStatus.
Set num_events_max in Buildbot's WebStatus.

BUG=none
TEST=num_events is limited to 3000

Review URL: http://codereview.chromium.org/6606009

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@76596 0039d316-1c4b-4281-b951-d872f2087c98

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