Update URL for Informix Client SDK (closes #156)

Author: jimwins

entities/global.ent

@@ -160,7 +160,7 @@
 <!ENTITY url.imap.book "http://oreilly.com/catalog/9780596000127/">
 <!ENTITY url.imode "http://www.nttdocomo.com/services/imode/">
 <!ENTITY url.informix.connectionstring "https://www.ibm.com/docs/en/informix-servers/14.10?topic=sources-connection-string-keywords-that-make-connection">
-<!ENTITY url.informix.csdk "https://www.ibm.com/products/informix/developer-tools/">
+<!ENTITY url.informix.csdk "https://www.ibm.com/support/pages/download-informix-products">
 <!ENTITY url.informix.dsn "https://www.ibm.com/docs/en/informix-servers/14.10?topic=guide-configure-data-sources">
 <!ENTITY url.ingres.downloads "http://esd.ingres.com/">
 <!ENTITY url.ingres.peclext "http://esd.ingres.com/product/drivers/PHP/">