python3: un-break disabling the readline PACKAGECONFIG

Previously the readline module would have been built regardless of
readline's presence in the sysroot, and the recipe would
fail at package_qa.

(From OE-Core rev: 79ebbca6943bc66b619671f93ac283ed2cfc8e5c)

Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python3_3.7.4.bb

@@ -102,6 +102,7 @@ do_configure_prepend () {
     cat > ${B}/Modules/Setup.local << EOF
 *disabled*
 ${@bb.utils.contains('PACKAGECONFIG', 'gdbm', '', '_gdbm _dbm', d)}
+${@bb.utils.contains('PACKAGECONFIG', 'readline', '', 'readline', d)}
 EOF
 }