tests: avoid checking the exitcode of false
Solaris false returns 255 instead of 1, so we remove one unneeded instance and
replaces another with (exit 1) as suggested by Brodie Rao.
% prepare repo
adding a
% import patch
applying patch from stdin
patching file a
Hunk #1 succeeded at 43 (offset 34 lines).
Hunk #2 succeeded at 87 (offset 34 lines).
Hunk #3 succeeded at 109 (offset 34 lines).
a
% compare imported changes against reference file