libio: Synthesize ESPIPE error if lseek returns 0 after reading bytes

libio: Synthesize ESPIPE error if lseek returns 0 after reading bytes

This is required so that fclose, when trying to seek to the right
position after filling the input buffer, does not fail with EINVAL.
This fclose code path only ignores ESPIPE errors.

Reported by Petr Pisar on
<https://bugzilla.redhat.com/show_bug.cgi?id=2358265>.

Fixes commit be6818be31e756398e45f70e2819d78be0961223 ("Make fclose
seek input file to right offset (bug 12724)").

Reviewed-by: Frédéric Bérat <fberat@redhat.com>