tests: avoid failure on w32 file systems.

[Ralf Wildenhues]

Obvious omission I didn't think of.  This is for maint,
I'll push tomorrow.

Cheers,
Ralf

    tests: avoid failure on w32 file systems.
    
    * tests/parallel-tests-unreadable-log.test: SKIP if file cannot
    be turned unreadable.

diff --git a/tests/parallel-tests-unreadable-log.test 
b/tests/parallel-tests-unreadable-log.test
index 6ebb2b6..572f03d 100755
--- a/tests/parallel-tests-unreadable-log.test
+++ b/tests/parallel-tests-unreadable-log.test
@@ -51,6 +51,7 @@ line=PASS; export line
 $MAKE foo.log
 $MAKE bar.log
 chmod a-r foo.log bar.log
+test ! -r foo.log || Exit 77
 $MAKE test-suite.log >stdout && { cat stdout; Exit 1; }
 cat stdout
 grep '^2 of 2 tests failed *$' stdout