Fix running of Haskell tests

Commit 21a5e56c forgot to rename a variable used in a conditional (of
course shell didn't complain about unused vars), so the AM_CONDITIONAL
was always false.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Adeodato Simo <dato@google.com>

configure.ac

@@ -575,7 +575,7 @@ if test "$HTOOLS" != "yes" && test "$ENABLE_CONFD" = "True"; then
 fi
 
 AM_CONDITIONAL([WANT_HTOOLS], [test x$HTOOLS = xyes])
-AM_CONDITIONAL([WANT_HTOOLSTESTS], [test "x$GHC_PKG_QUICKCHECK" != x])
+AM_CONDITIONAL([WANT_HTOOLSTESTS], [test "x$HTOOLS_NODEV" = x])
 AM_CONDITIONAL([WANT_HTOOLSAPIDOC], [test x$HTOOLS_APIDOC = xyes])
 AM_CONDITIONAL([HAS_HLINT], [test "$HLINT"])