adb: fix adb_close() vs. unix_close() usage

Document the differences between adb_*() and unix_*() in the function
prototypes in sysdeps.h. See the file for the details (CR/LF
translation, well-known file descriptors, etc.).

Fix adb_read(), adb_write(), and adb_close() calls that should really be
unix_read(), unix_write(), and unix_close(). Note that this should have
no impact on unix because on unix, unix_read/unix_write/unix_close are
macros that map to adb_read/adb_write/adb_close.

Improve sysdeps_win32.cpp file descriptor diagnostic logging to output
the name of the function that was passed a bad file descriptor.

Change-Id: I0a1d9c28772656c80bcc303ef8b61fccf4cd637c
Signed-off-by: Spencer Low <CompareAndSwap@gmail.com>