lib/updater: fix invalid hash check for SHA256

This is major problem as packages were not verified thanks to this
error.

This also adds warning for packages not correctly verified.
6 jobs for 3x-fix-invalid-hash in 2 minutes and 58 seconds (queued for 9 seconds)
Status Job ID Name Coverage
  Test
passed #377749
cppcheck

00:00:52

passed #377750
luacheck

00:00:55

passed #377747
system-tests

00:01:34

passed #377748
system-valgrind-tests

00:02:58

passed #377745
unit-tests

00:01:22

passed #377746
unit-valgrind-tests

00:02:44