android_filesystem_config.h is found since system/core/include is on
the include path for all projects and contains a symlink to the real
android_filesystem_config.h. This is fragile and the below bug seeks
to remove this symlink and have users correctly depend on
libcutils_headers.
Bug: 165825252
Test: build
Change-Id: I1aad6a2e8fbe87635e97b0ac1be3414403353382