Remove references to NonMatchineMachines exception.

NonMatchingMachines was removed in a CL yesterday, but a few
references to it were missed.  This removes those references.

BUG=None
TEST=None

Change-Id: Iadc75d26bce6193d30c23c22b5fc1a529103b607
Reviewed-on: https://chrome-internal-review.googlesource.com/229501
Commit-Ready: Caroline Tice <cmtice@google.com>
Tested-by: Caroline Tice <cmtice@google.com>
Reviewed-by: Yunlian Jiang <yunlian@google.com>
2 files changed