Bazel: Remove deprecated tls_enabled option

This option was flipped in context of:[1] and is now enabled per
default. When running gerrit build with remote execution strategy,
this warning is issued:

  WARNING: Option 'tls_enabled' is deprecated: No-op. See #8061 \
  for details.

[1] bazelbuild/bazel#8061

Change-Id: I6d77f08e483157f955e82abe0bae848075a7040e

tools/remote-bazelrc

@@ -70,9 +70,6 @@ build:remote --remote_cache=remotebuildexecution.googleapis.com
 # Enable remote execution so actions are performed on the remote systems.
 build:remote --remote_executor=remotebuildexecution.googleapis.com
 
-# Enable encryption.
-build:remote --tls_enabled=true
-
 # Set a higher timeout value, just in case.
 build:remote --remote_timeout=3600