fix LOCAL_JAVACFLAGS

don't override -g option

Change-Id: I94ffeb5f45a2332cf872a5c6e86cf207d3d39ecb
diff --git a/Android.mk b/Android.mk
index dcdc657..7db99fe 100644
--- a/Android.mk
+++ b/Android.mk
@@ -21,14 +21,13 @@
 
 LOCAL_JAVA_RESOURCE_DIRS := res
 
-LOCAL_JAVACFLAGS := -g
+LOCAL_JAVACFLAGS += -g -Xlint
 
 LOCAL_MODULE := tradefed
 
 LOCAL_MODULE_TAGS := optional
 LOCAL_STATIC_JAVA_LIBRARIES := junit kxml2-2.3.0 guavalib jline-1.0
 LOCAL_JAVA_LIBRARIES := ddmlib-prebuilt
-LOCAL_JAVACFLAGS = -Xlint
 
 include $(BUILD_HOST_JAVA_LIBRARY)