graphics/sane-backends: Actually update to 1.0.27

The current version is 1.0.25 with a wrongly named distfile which
fails to fetch from the fossies.org mirror with a size mismatch.
The update to 1.0.27 in r444767 also shows that the checksum and
size have not changed in distinfo in that commit. Full changes
between the distfiles from 1.0.27_4 & 1.0.27_5 can be found at [1].

• Remove dead alioth.debian.org mirror
• Remove some no longer needed patches

[1] https://people.freebsd.org/~tobik/logs/sane-backends-1.0.27.diff

ABI: https://abi-laboratory.pro/tracker/timeline/sane-backends/
PR: 229653
Submitted by: Peter Wullinger <freebsd@dhke.de>