releasetools: Abort the update on apply_patch failures.

We used to silently ignore the return value from apply_patch() even if
it had failed. It gives us more trouble to investigate the failure when
the affected file/partition gets touched in subsequent OTAs. This CL
adds the checking of the return value and aborts the update accordingly.

Bug: 25893277
Change-Id: Ie5e1c563576e503343e6a5b28ed4d7039f6f919c