Jaeger Agent adding collector endpoint to user-provided list of collectors

[jpkrohling]

Describe the bug
When running the all-in-one, specifying the parameter --reporter.grpc.host-port should result in the agent using that parameter as the list of collectors to connect to. Instead, the agent is adding its own collector to the list:

To Reproduce
Steps to reproduce the behavior:

1. go run ./cmd/all-in-one/main.go --query.static-files jaeger-ui/packages/jaeger-ui/build --collector.grpc-server.host-port :14251 --reporter.grpc.host-port localhost:14250

From the logs:

{"level":"info","ts":1593093249.0338247,"caller":"grpc/builder.go:86","msg":"Agent is connecting to a static list of collectors","dialTarget":"c3q8fb7dyt3d:///round_robin","collector hosts":"localhost:14250,:14251"}

Expected behavior
The agent's list of collectors to connect to includes only localhost:14250

Screenshots
n/a

Version (please complete the following information):

• OS: Fedora 32 w/ latest updates
• Jaeger version: latest master as of now (1f70cab69fbd454e7d3013755e8d7a64bc0f8063)
• Deployment: bare metal

What troubleshooting steps did you try?
n/a