Reproduce the ruby_grpc_compile issue in #67

[kalbasit]

This pull request is not meant to be merged. Instead, I'm filing it as a reproducible example of an issue I encountered when using ruby_grpc_compile.

GitHub issue: #67

λ uname -a
Darwin poseidon 19.4.0 Darwin Kernel Version 19.4.0: Wed Mar  4 22:28:40 PST 2020; root:xnu-6153.101.6~15/RELEASE_X86_64 x86_64

λ bazel version
Build label: 3.1.0-homebrew
Build target: bazel-out/darwin-opt/bin/src/main/java/com/google/devtools/build/lib/bazel/BazelServer_deploy.jar
Build time: Thu May 14 23:56:31 2020 (1589500591)
Build timestamp: 1589500591
Build timestamp as int: 1589500591

λ bazel build //example/ruby/ruby_grpc_compile:greeter_ruby_grpc
INFO: Analyzed target //example/ruby/ruby_grpc_compile:greeter_ruby_grpc (0 packages loaded, 0 targets configured).
INFO: Found 1 target...
ERROR: /Users/yl/code/keeptruckin/stories/PLATF-5084/src/github.com/rules-proto-grpc/rules_proto_grpc/example/proto-status/BUILD.bazel:1:1: output 'example/proto-status/status_proto/ruby_grpc_compile_aspect_verb0/example/proto-status/status_services_pb.rb' was not created
ERROR: /Users/yl/code/keeptruckin/stories/PLATF-5084/src/github.com/rules-proto-grpc/rules_proto_grpc/example/proto-status/BUILD.bazel:1:1: not all outputs were created or valid
Target //example/ruby/ruby_grpc_compile:greeter_ruby_grpc failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 0.167s, Critical Path: 0.04s
INFO: 3 processes: 3 darwin-sandbox.
FAILED: Build did NOT complete successfully


λ ls bazel-out/darwin-fastbuild/bin/example/proto-status/status_proto/ruby_grpc_compile_aspect_verb*/example/proto-status/
bazel-out/darwin-fastbuild/bin/example/proto-status/status_proto/ruby_grpc_compile_aspect_verb0/example/proto-status/:
status_pb.rb

bazel-out/darwin-fastbuild/bin/example/proto-status/status_proto/ruby_grpc_compile_aspect_verb1/example/proto-status/:
status_pb.rb

bazel-out/darwin-fastbuild/bin/example/proto-status/status_proto/ruby_grpc_compile_aspect_verb4/example/proto-status/:
status_pb.rb