[infer] Fix a typo in Makefile of build test

Reviewed By: jvillard

Differential Revision: D21950620

fbshipit-source-id: 0fd569948

infer/tests/build_systems/ant/Makefile

@@ -9,7 +9,7 @@ SOURCES = $(wildcard src/*.java)
 CLASS_FILES = $(notdir $(patsubst %.java,%.class,$(SOURCES)))
 OBJECTS = $(CLASS_FILES:%=ant_out/%)
 INFERPRINT_OPTIONS = --issues-tests
-CLEAN_EXTRA = ant-out
+CLEAN_EXTRA = ant_out
 
 include $(TESTS_DIR)/java.make
 include $(TESTS_DIR)/infer.make