dashboard/retrybuilds: add more flaky phrases
dashboard/retrybuilds: add more flaky phrases

Change-Id: Id1a1b870a348a24040d94b157328b1632776711f
Reviewed-on: https://go-review.googlesource.com/1877
Reviewed-by: Dave Cheney <bfcdf3e6ca6cef45543bfbb57509c92aec9a39fb@cheney.net>

proppy/build,golang/build,proppy/build,golang/build,evandbrown/build,evandbrown/build,golang/build,evandbrown/build,proppy/build,golang/build,proppy/build