Use unix:// instead of unix:

unix:/home/user/.cache/bb_clientd/grpc does not work with Bazel,
but unix:///home/user/.cache/bb_clientd/grpc does work. Update README.md
accordingly.

Author: moroten

README.md

@@ -119,7 +119,7 @@ bazel build --remote_executor mycluster-prod.example.com --remote_instance_name
 You can let it use bb\_clientd by running it like this instead:
 
 ```
-bazel build --remote_executor "unix:${XDG_CACHE_HOME:-${HOME}/.cache}/bb_clientd/grpc" --remote_instance_name mycluster-prod.example.com/hello [more options]
+bazel build --remote_executor "unix://${XDG_CACHE_HOME:-${HOME}/.cache}/bb_clientd/grpc" --remote_instance_name mycluster-prod.example.com/hello [more options]
 ```
 
 Notice how the hostname of the cluster has become a prefix of
@@ -143,7 +143,7 @@ name acts as its own namespace. This means that if you want to cache the
 results of a build performed locally, you may run Bazel as follows:
 
 ```
-bazel build --remote_cache "unix:${XDG_CACHE_HOME:-${HOME}/.cache}/bb_clientd/grpc" --remote_instance_name local/some/project --remote_upload_local_results=true [more options]
+bazel build --remote_cache "unix://${XDG_CACHE_HOME:-${HOME}/.cache}/bb_clientd/grpc" --remote_instance_name local/some/project --remote_upload_local_results=true [more options]
 ```
 
 The advantage of this option over Bazel's own `--disk_cache` flag is
@@ -257,5 +257,5 @@ Bazel can be configured to use this feature by providing the following
 additional command line arguments:
 
 ```
---experimental_remote_output_service "unix:${XDG_CACHE_HOME:-${HOME}/.cache}/bb_clientd/grpc" --experimental_remote_output_service_output_path_prefix "${HOME}/bb_clientd/outputs"
+--experimental_remote_output_service "unix://${XDG_CACHE_HOME:-${HOME}/.cache}/bb_clientd/grpc" --experimental_remote_output_service_output_path_prefix "${HOME}/bb_clientd/outputs"
 ```