Revert "Do not build if HAVE_SELINUX=false."

We need to always build libselinux even if it's not being used by
anything in the system image. This makes sure some unrelated change
doesn't accidentally break libselinux.

This reverts commit 6670f53f78cd44a6cb484785b2837439e2ba9178.
diff --git a/Android.mk b/Android.mk
index c8d5083..b530040 100644
--- a/Android.mk
+++ b/Android.mk
@@ -1,5 +1,3 @@
-ifeq ($(HAVE_SELINUX), true)
-
 LOCAL_PATH:= $(call my-dir)
 
 common_SRC_FILES := \
@@ -70,5 +68,3 @@
 LOCAL_COPY_HEADERS := $(common_COPY_HEADERS)
 LOCAL_PRELINK_MODULE := false
 include $(BUILD_SHARED_LIBRARY)
-
-endif # ifeq ($(HAVE_SELINUX, true)