Merge "log more info on fence sync_merge error" into jb-mr1-dev

    ATRACE_CALL();

    int result = sync_merge(name.string(), f1->mFenceFd, f2->mFenceFd);

    if (result == -1) {

        ALOGE("merge: sync_merge returned an error: %s (%d)", strerror(-errno),

                errno);

        status_t err = -errno;

        ALOGE("merge: sync_merge(\"%s\", %d, %d) returned an error: %s (%d)",

                name.string(), f1->mFenceFd, f2->mFenceFd,

                strerror(-err), err);

        return NO_FENCE;

    }

    return sp<Fence>(new Fence(result));