Adds the mergeRequests field to builders.pyl.
Adds the mergeRequests field to builders.pyl.

This field tells buildbot to merge together duplicate requests. This CL allows
users to override the default behavior builders.pyl had, which is True if the
builder has a named scheduler, and False otherwise.

R=dpranke@chromimum.org

BUG=

Review URL: https://codereview.chromium.org/1396243004

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@297144 0039d316-1c4b-4281-b951-d872f2087c98

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