adb: added support for adb pull -a to preserve time stamps and mode

Added -a flag to adb pull that preserves time and mode.  Mode is
subjected to umask for security.  We only receive modification
time from adb server, so creation time will be set to the modification
time as well.

Signed-off-by: Lajos Molnar <lajos@google.com>

(cherry picked from commit de8ff4ad)

Change-Id: I03bb5cc14ce542299cf3b221a8be318a28ee8a8d