am 98e67d35: Don\'t corrupt parcel when writeFileDescriptor() fails

restart_write:

        *reinterpret_cast<flat_binder_object*>(mData+mDataPos) = val;

        // Need to write meta-data?

        if (nullMetaData || val.binder != 0) {

            mObjects[mObjectsSize] = mDataPos;

            acquire_object(ProcessState::self(), val, this);

            mObjectsSize++;

        }

        // remember if it's a file descriptor

        if (val.type == BINDER_TYPE_FD) {

            if (!mAllowFds) {

                // fail before modifying our object index

                return FDS_NOT_ALLOWED;

            }

            mHasFds = mFdsKnown = true;

        }

        // Need to write meta-data?

        if (nullMetaData || val.binder != 0) {

            mObjects[mObjectsSize] = mDataPos;

            acquire_object(ProcessState::self(), val, this);

            mObjectsSize++;

        }

        return finishWrite(sizeof(flat_binder_object));

    }