Use more aggressive sync writing to applypatch.

We have seen cases where the boot partition is patched, but upon
recovery the partition appears to be corrupted.  Open up all
patched files/partitions with O_SYNC, and do not ignore the
errors from fsync/close operations.

Bug: 18170529
Change-Id: I392ad0a321d937c4ad02eaeea9170be384a4744b