remove unused build args (#6697)

Author: zirain

.bazelrc

@@ -15,7 +15,6 @@ build:remote --remote_timeout=7200
 
 # Enable libc++ and C++20 by default.
 build:linux --config=clang
-build:linux --define=LLVM_DIRECTORY=/usr/lib/llvm
 
 # put /usr/local/bin before /usr/bin to avoid picking up wrong python3.6 when building envoy.tls.key_providers.cryptomb
 build:linux --action_env=PATH=/usr/lib/llvm/bin:/usr/local/bin:/bin:/usr/bin