test 209: bad CONFIG_SITE check fails with AIX 5.1 sh

[Ralf Wildenhues]

Seems we can't rely on dot returning an error status; this is the only
failure on AIX 5.1 with /bin/sh and current git plus one unrelated
patch:

../../autoconf/tests/base.at:412: grep 'whether true.*works.*cached' stdout
+ grep whether true.*works.*cached stdout
stdout:
checking whether true(1) works... (cached) yes
+ cat
+ 1> bad.site 0< /tmp/sh925826.1531
+ CONFIG_SITE=/tmp/tests/testsuite.dir/209/bad.site
../../autoconf/tests/base.at:419: ./configure $configure_options 
+ ./configure
stderr:
./configure[1550]: syntax error at line 2 : `fi' unexpected
stdout:
configure: loading site script /tmp/tests/testsuite.dir/209/bad.site
../../autoconf/tests/base.at:419: exit code was 0, expected 1
config.log:
> This file contains any messages produced by compilers while
> running configure, to aid debugging if configure makes a mistake.
> 
> It was created by configure, which was
> generated by GNU Autoconf 2.65.92-f90f2.  Invocation command line was


Cheers,
Ralf