Workaround for bash bug in tests/yacc8.test

[Pavel Roskin]

Hello!

Today's CVS Automake fails in yacc8.test on RedHat Linux 7.2 with 
bash 2.05.8(1)-release.

The failure only happens when VERBOSE=1 is not specified and bash is used.  
Using ash or pdksh fixes the problem.

Even adding a comment between "test" and "cd" fixes the problem.  This
patch adds "exit 1" - it also increases readability, since "set -e" is far
away.

ChangeLog:
        * tests/yacc8.test: Add a command between "test" and "cd" to work
        around a bug in bash-2.05.

=======================
--- tests/yacc8.test
+++ tests/yacc8.test
@@ -58,7 +58,7 @@
 END
 
 $AUTOMAKE -a
-test -f ./ylwrap
+test -f ./ylwrap || exit 1
 
 cd sub
 make foo/parse2.o
=======================

-- 
Regards,
Pavel Roskin