adb/base: allow use of unique_fd inside adb.

adb implements its own file descriptor emulation layer on Windows,
which requires the use of adb_close instead of close throughout the
codebase. Add a template argument to unique_fd that allows for this.

Bug: http://b/28347842
Change-Id: I6397261f4973d49f2f8e04257bf67b348585bb63