adb: fix adb install and adb push exit code, error handling, unittest

adb push was not returning a bad exit code when write_data_file() or
write_data_link() failed. I encountered this when running the unittest
on Windows which can get into situations where stat() succeeds, but
open() fails due to pre-existing exclusive file access (which typically
doesn't exist on unix).

The same code is used by adb install, so this also fixes its error
handling.

Fixed some fd leaks and propagation of errors when reading a file.

Fixed a unittest to close temp files before reading them.

Change-Id: Ieba0026fa4c79eb0484676e4f2faaac9603ef584
Signed-off-by: Spencer Low <CompareAndSwap@gmail.com>