Allow composd to run fd_server

Besides the basic execution that is similar to the (deprecating)
odrefresh case, fd_server also needs to be able to create and change
files in the output directory.

Bug: 205750213
Test: /apex/com.android.compos/bin/composd_cmd forced-odrefresh
      # Saw composd started the fd_server and the VM
Change-Id: Ia66015b72c4bd232c623604be326c7d7145c0a38
3 files changed