[infer][java] export the analyzer used and the version of Infer as an environment variable that can be read from BUCK files

Reviewed By: sblackshear

Differential Revision: D4006125

fbshipit-source-id: ea5decd

infer/lib/python/inferlib/bucklib.py

@@ -92,6 +92,7 @@ def prepare_build(args):
 
     # Export the Infer command as environment variables
     os.environ['INFER_JAVA_BUCK_OPTIONS'] = json.dumps(infer_command)
+    os.environ['INFER_RULE_KEY'] = utils.infer_key(args.analyzer)
 
     # Create a script to be called by buck
     infer_script = None