Export top level directory

libexif headers expect to be exported as libexif/*.h.

Test: m -j checkbuild
Change-Id: I7cb1e2069584e0d4b2b1444237e427381bcdc4cd
diff --git a/Android.bp b/Android.bp
index 87c3af9..308bcb2 100644
--- a/Android.bp
+++ b/Android.bp
@@ -46,7 +46,7 @@
         "libexif/pentax/mnote-pentax-tag.c",
     ],
 
-    export_include_dirs: ["libexif"],
+    export_include_dirs: ["."],
 
     cflags: [
         "-ftrapv",