Bazel doesn't provide a way to exclude scanning directories in project
root: [1]. Add workaround, by teaching Eclipse to exclude BUILD file
instead. With this workaround in place Eclipse and Bazel build can
co-exist:
$ tools/eclipse/project.py # generates .classpath and other files
# Start Eclipse and rebuild gerrit, eclipse-out is created
$ bazel test ... # works as expected now
[1] https://github.com/bazelbuild/bazel/issues/1083
Change-Id: I7e767d0768af8bba3acc84d5fc242cab0e9abfdb
19b60b5527