make check-pylint: Fix false negatives introduced in 72219bdb
make check-pylint: Fix false negatives introduced in 72219bdb

Surprisingly (to me, at least) the change in 72219bdb causes `$r`
to *not* be set to `1` when `pylint` fails. The following experiment
confirms the confusing behaviour:

    $ r=0; { echo hi; false || r=1; }; echo $r
    hi
    1

    $ r=0; { echo hi; false || r=1; } | grep -v hi; echo $r
    0

wmanley/stb-tester,LewisHaley/stb-tester,wmanley/stb-tester,stb-tester/stb-tester,martynjarvis/stb-tester,martynjarvis/stb-tester,LewisHaley/stb-tester,martynjarvis/stb-tester,LewisHaley/stb-tester,LewisHaley/stb-tester,LewisHaley/stb-tester,stb-tester/stb-tester,martynjarvis/stb-tester,wmanley/stb-tester,martynjarvis/stb-tester,wmanley/stb-tester,martynjarvis/stb-tester,stb-tester/stb-tester,LewisHaley/stb-tester,martynjarvis/stb-tester,wmanley/stb-tester,stb-tester/stb-tester,LewisHaley/stb-tester